These are some websites / bookmarks that I'm trying to put some shape around.
The space is confusing, as many organisations may wear multiple hats.
For example what is R3? - Is it a fabric? (Corda), is it an application?, is it a consortia?
It's actually a bit of each.
The below is as much for my benefit a 'disambiguation'.

If you see any others firms / links / applications...that you think are relevant to the blockchain space...just let me know.

Blockchains (fabric)

I start with the fabrics (or 'blockchains').
If you want to get a feel for how active the community is around a fabric, try having a look around GitHub (which gives a feel for numbers of users, commits, community etc.)
When people pick a fabric....they don't just make their decision on the raw technology - it's also about how vibrant the community is ~(e.g. online support to help you through those head scratching moments).
https://github.com/

Blockchain.info
The Bitcoin blockchain...I won't say where it all began, rather where it went mainstream.
https://blockchain.info/api
..and a link to Satoshi's white paper.
https://bitcoin.org/bitcoin.pdf

Ethereum
Needs no introduction. The first of the fabrics to gain mainstream 'acceptance'.
https://www.ethereum.org/

Hyperledger
IBM's offering. Branding and some code injected by Digital Asset.
https://www.hyperledger.org/
Version 1.0 (Mar '17), Release notes.
http://hyperledger-fabric.readthedocs.io/en/latest/abstract_v1.html
Great PoC tracker here:
https://www.hyperledger.org/industries/finance#poc_tracker

Corda
R3's contribution.
https://www.corda.net/

Credits

~~Which appears to have gone through a hic-cup:~~
~~https://www.fnlondon.com/articles/blockchain-startup-hits-the-rocks-after-owner-spat-20170725~~
~~(Their old website, now inactive was: http://credits.vision/)~~
A totally unrelated Russian entity (co-incidentally with the same name) have their ICO details at:
https://credits.com/en

Qad.re
https://www.qad.re/
Credits team re-invented and restructured.
Their DLT offering: Plug.
http://www.cityam.com/282566/blockchain-group-plug-has-just-raised-65m-develop-its

Ripple

...and the colourful history of Jed McCaleb.

https://www.cryptocoinsnews.com/ripple-co-founder-jed-mccaleb-announces-sell/

Jed is part of Bitcoin folklaw. He started a trading exchange (think eBay) for: Magic The Gathering trading cards, Online Exchange (i.e: MtGox).

https://ripple.com/

Stellar
https://www.stellar.org/how-it-works/use-cases/

Axoni Core
Axoni’s proprietary distributed ledger software.
https://axoni.com/home

NXT

https://nxt.org/

Bankchain
Paxos is the Capital Markets 'demerged' part of the itBit business.
https://www.itbit.com/
Their blockchain is....
https://www.paxos.com/bankchain

MultiChain
[MultiChain was forked from Bitcoin Core]
http://www.multichain.com/blog/
What is also interesting are some of the Multichain partners (including): Accenture, Boston Consulting Group and pwc.
http://www.multichain.com/platform-partners/

Chain

Open Standard for Blockchain (protocol for high-scale applications)

http://chain.com/

Quorum
An interesting spin. JPMorgan's DLT based on Ethereum
https://www.jpmorgan.com/Quorum

Symbiont Assembly
Symbiont Assembly is the DLT that powers Symbiont applications:
https://symbiont.io/
https://symbiont.io/blog/2016/10/18/introducing-symbiont-assembly

Bloq
http://www.bloq.com/

Universa Blockchain Protocol
https://universa.io/

OpenChain
Openchain is an open source distributed ledger technology
https://www.openchain.org/

Cobalt DL
http://www.cobaltdl.com/

Counterparty
Counterparty stores data in regular bitcoin transactions
https://counterparty.io/

æternity
https://www.aeternity.com/

Blockchain Consortia

We also have some consortia that use these fabrics...

R3 Cev
https://r3cev.com/
...Industry consortium...but is it?
...they also provide a chain / fabric: Corda
...and they will have solutions, which I guess they'll try to bring to market (monetise).
e.g. https://r3cev.com/projects/
(This is the Barclays Smart Contract Template as demonstrated with an ISDA master agreement)

Hyperledger
Operating under the Linux Foundation.
https://www.hyperledger.org/
....created to advance blockchain technology...
Yep, the consortium uses the same working title as their Fabric....just to make it easy for us.
https://www.hyperledger.org/about/members
All the members are interesting, however a couple of note:
Central Market Infrastructures: CME, Deutsche Bourse, DTCC, CLS, Moscow Exchange, NSE, Swift, TMX
Capital Markets: R3, JPM, ABN, ANZ, BBVA, BNP, BNY, Shroders, State Street, Wells Fargo
Vendors: IBM, Digital Asset, Broadridge, Symbiont

Liquidshare
Liquidshare has been created by BNP Paribas, CACEIS, Caisse des Dépôts, Euroclear, Euronext, S2iEM and Société Générale with the support of Paris Europlace.
https://www.finextra.com/newsarticle/30818/liquidshare-dlt-joint-venture-formed-by-seven-strong-finance-consortium

Enterprise Ethereum
Their Mission:
A clear roadmap for enterprise features and requirements
Robust governance model and accountability, clarity around IP and licensing models for open source technology
Resources for businesses to learn about Ethereum and leverage this groundbreaking technology to address specific industry use cases
https://entethalliance.org/members/
All the members are interesting, however a couple of note:
Central Market Infrastructures: CME, DTCC
Capital Markets: BBVA, BNY, CS, ING, JPM, Santander, State Street, UBS
Vendors: Broadridge, Consensys, Microsoft

Chain

Global Financial Firms:

See also Fabric
Capital One, Citigroup, Fidelity, First Data, Fiserv, MUFG, Nasdaq, State Street and Visa

Unveil Open Standard for Blockchain (protocol for high-scale applications)

http://chain.com/

Blockchain Research Institute (BRI).
Don Tapscott and Alex Tapscott, co-authors of the best-selling book Blockchain Revolution are pleased to announce the formation of the Blockchain Research Institute (BRI).
Founding Members:
Technology Industry – Accenture, IBM, SAP
Financial Industry – Digital Asset, NASDAQ
Global Corporations – Pepsico, Centrica, Liberty Global
Government – Province of Ontario, University Health Network
Blockchain Pioneers – Nuco Inc., Paycase, Artlery, Votem, Cosmos, Youbase, Wisekey
Affiliate Organizations – The Hyperledger Project, the Chamber of Digital Commerce, Coala.io, Enterprise Ethereum Alliance
http://www.the-blockchain.com/2017/03/16/multi-million-dollar-research-institute-launched-explore-blockchain-use-cases-opportunities-challenges/

Institute for Development and Research in Banking Technology [IDRBT]
Established by the Reserve Bank of India in March 1996 as an Autonomous Centre for Development and Research in Banking Technology.
Their first white paper on DLT. (88 pages).
http://www.idrbt.ac.in/whitepapers.html

Blockchain Insurance Industry Initiative B3i Grows to 15 Members
The current members of B3i are Achmea, Aegon, Ageas, Allianz, Generali, Hannover Re, Liberty Mutual, Munich Re, RGA, SCOR, Sompo Japan Nipponkoa Insurance, Swiss Re, Tokio Marine Holdings, XL Catlin and Zurich Insurance Group. (The original five members were Aegon, Allianz, Munich Re, Swiss Re and Zurich.)
http://www.insurancejournal.com/news/international/2017/02/06/440629.htm

Swift recruits CSDs for DLT post trade plans.
The consortium of seven CSDs comprise Abu Dhabi Securities Exchange, Caja de Valores (Argentina), Depósito Central de Valores (Chile), Nasdaq Market Technology AB, National Settlement Depository (Russia), SIX Securities Services and Strate Ltd and Swift hopes to recruit more CSDs in the coming weeks.
https://www.finextra.com/newsarticle/31530/swift-recruits-csds-for-dlt-post-trade-plans?utm_medium=dailynewsletter&utm_source=2018-1-17&member=58717

Blockchain Vendors / Solutions

Obviously this list is not extensive and ever evolving. Just say WIP (work in progress).
If you see this, and you're not here, sorry, reach out and I'll amend.
Likewise, if you need to engage with any of these firms or need technical project management please also free to get in contact!

UK

http://appliedblockchain.com/
L39: Developers of private blockchain solutions and applications

https://ethcore.io/
From those nice chaps that brought us
https://www.ethereum.org/

Provider of technology to physical commodity markets
http://www.kynetix.com/

https://www.bigchaindb.com/

The scalable blockchain database.

http://www.adnovum.ch/en/

Digital Asset
https://digitalasset.com/
https://digitalasset.com/about.html#investors
Digital asset builds distributed, encrypted straight through processing tools. Our technology improves efficiency, security, compliance and settlement speed.

Axoni
https://axoni.com/about
...provider of distributed ledger technology to the financial services industry..
May 17: Citi has joined its Series A funding round, bringing the total amount raised to over $20 million.
https://axoni.com/updates/citi-joins-axonis-financing-round-bringing-total-raise-to-over-20-million

Consensys
https://consensys.net/
ConsenSys is a venture production studio focused on building and scaling tools, disruptive startups, and enterprise software products powered by decentralized technology, specifically Ethereum.

Tendermint
http://tendermint.com/

...bringing simplicity, security, and speed to the world’s blockchains.

Bloq

http://bloq.com/index.html
Our software solution, BloqEnterprise, has five key offerings that enable users to create, test, update, customize and analyize their own public, private and permissioned blockchains.
...i.e. chain agnostic.

Wipro

http://www.wipro.com/microsite/blockchain/resource.php
https://www.wipro.com/

Aust

http://finhaus.com.au/

commercial research, development and delivery of Blockchain technology projects

http://stoneandchalk.com.au/

independent, not-for-profit Fintech hub

RoW

Israel
Coin Sciences...(http://www.gidgreen.com/) aka..
http://www.multichain.com/
Open platform for blockchain applications

Argentina
http://www.rsk.co/
Rootstock...RSK provides the missing technical needs, as a blockchain with a 2way peg to Bitcoin.

India
http://www.utradesolutions.com/
uTrade is a FinTech company providing multi-asset trading platform,low latency algos engine,
risk management and Blockchain Solutions.

Blockchain Links

Useful Links

A great introduction: How Bitcoin Works Under the Hood
https://youtu.be/Lx9zgZCMqXE

Data is everywhere, but at Data61 it’s also everything...
https://research.csiro.au/data61/blockchain/

ensure payments are simple and secure for Kiwis
http://www.paymentsnz.co.nz/

Interesting Papers

The future of financial infrastructure: An ambitious look at how blockchain can reshape financial services
https://www.weforum.org/reports/the-future-of-financial-infrastructure-an-ambitious-look-at-how-blockchain-can-reshape-financial-services

Investors

Digital Asset Holdings / Blythe Masters
Making waves in the blockchain space having recently acquired Hyperledger, Bits of Proof and Blockstack.io, as it bids to build out its portfolio.
http://digitalasset.com/

https://blockchain.info/

Great reference site for all the stats and info on the Bitcoin blockchain.

Raised US$30.5myn. [Series A (2014)]

Investor Investor Type Location
Lightspeed Venture Partners Venture Capital Menlo Park, California, United States
Mosaic Ventures Venture Capital United Kingdom
Prudence Holdings Private Equity New York, New York, United States
Richard Branson Angel Investor (Individual) United Kingdom
Wicklow Capital Family Office Chicago, Illinois, United States

coinbase.comCoinbase is a bitcoin wallet and platform where merchants and consumers can transact with the new digital currency bitcoin.
Investor* Investor Type Location
Reinventure (WestPac) Venture Capital Australia
Andreessen Horowitz Venture Capital Menlo Park, California, United States
BBVA Ventures Corporate Venture San Francisco, California, United States
DFJ Growth Fund Venture Capital Menlo Park, California, United States
NTT DoCoMo Ventures Corporate Japan
NYSE Euronext Corporation New York, New York, United States
Ribbit Capital Venture Capital Palo Alto, California, United States
Union Square Ventures Venture Capital New York, New York, United States
USAA Diversified Fin Svs San Antonio, Texas, United States
Vikram Pandit Angel Investor (Individual)
* not all investors listed.

http://blockchaintechcorp.com/
Acquired by Global Arena Holding, Inc. (OTC PINK: GAHC)
Custom Apps
Voting On The Blockchain
Time Stamping And Notaries
Bitcoin ATM Machines

Self Executing Wills And Contracts