There has been a solo pool for Bitcoin which has increased in popularity amongst some miners. This is a pool that unlike a normal pool, does not pay out regular small payments, but pays the miner the entire block reward of Bitcoins if they mine some (if you do not mine a block, you do not get paid). This is almost akin to a Bitcoin lottery, and you can use any size hardware to mine here, although your chances of finding a block are increased with more powerful hardware. This is called ‘solo’ mining.
There has been a case where someone with an Antminer S3 mined here and found a block within a month, getting the entire block reward, minus a small pool fee. The solo pool is a high speed, low latency pool which is connected to the Bitcoin relay network, a network which ensures fast block propagation to reduce the risk of an orphaned block.
This pool is hosted by the designer of cgminer, the mining application used by most ASIC mining companies and users. The pool can be found at solo.ckpool.org, with a port number of 3333. You simply put your wallet address as the username and the password as anything, and this is giving you a chance at the entire block reward! Maybe consider keeping a small rig on here so you get a chance to win, or some people rent large mining farms for a while in hopes of hitting the block. Hitting the block will reward you 12.5 Bitcoins + Transaction Fees.
Some point small USB stick miners there, others will point older more outdated hardware which they have no chance to profit from, and some will point a proportion or their entire farm of hardware there.
The pool has in the two years nearly it has been running has had less orphaned blocks than most major pools, which is a very low orphan rate for a pool. There was a recent incident with this pool where new code for the segwit activation was broadcast and it caused two found blocks on the pool to be rendered invalid. The pool operator, ck, fixed the code and reimbursed the miners out of his own pocket, something not many pool operators would do.
This pool is run by a person of integrity and it is the safest option to solo mine, much less of a risk of doing so than your own node due to latency problems and has always paid out. So why not give it a try, and dust off some of that old outdated hardware? You could win big!