This puzzle is very strange. If it's for measuring the world's brute forcing capacity, 161-256 are just a waste (RIPEMD160 entropy is filled by 160, and by all of P2PKH Bitcoin). The puzzle creator could improve the puzzle's utility without bringing in any extra funds from outside - just spend 161-256 across to the unsolved portion 51-160, and roughly treble the puzzle's content density.
If on the other hand there's a pattern to find... well... that's awfully open-ended... can we have a hint or two?

I am the creator.
You are quite right, 161-256 are silly. I honestly just did not think of this. What is especially embarrassing, is this did not occur to me once, in two years. By way of excuse, I was not really thinking much about the puzzle at all.
I will make up for two years of stupidity. I will spend from 161-256 to the unsolved parts, as you suggest. In addition, I intend to add further funds. My aim is to boost the density by a factor of 10, from 0.001*length(key) to 0.01*length(key). Probably in the next few weeks. At any rate, when I next have an extended period of quiet and calm, to construct the new transaction carefully.
A few words about the puzzle. There is no pattern. It is just consecutive keys from a deterministic wallet (masked with leading 000...0001 to set difficulty). It is simply a crude measuring instrument, of the cracking strength of the community.
Finally, I wish to express appreciation of the efforts of all developers of new cracking tools and technology. The "large bitcoin collider" is especially innovative and interesting!
Thank you @saatoshi_rising for this kind gesture, I appreciate you for making this puzzle an interesting one & for your funds you freely gave out to the community. In my humble suggestion, probably anytime you see this quote (that is if you would see it

), I humbly plead, you can make this puzzle more enticing by showing off the pub. key of some of the unspent addresses with a little spend maybe from the ± 101th key (± 101 i.e 2^100 - 2^160 keys or 2^99 - 2^71 keys), or keys with odd numbers (e.g key 71, 73, 75 etc) or keys with even numbers (e.g 72, 74, 82 etc) which ever you choose, at your own discretion or maybe randomly (e.g key 71, key 83, key 79 etc), probably between now and 2027 to mark 10 years anniversary you made this comment here

This puzzle is now at a very very difficult state almost impossible state, cracking bitcoin is even harder (impossible), these facts has been proven to be true no doubt. This puzzle has been on for 10yrs + and some people that saw it from the onset are no more (I hope the OP of this puzzle is very much more since Last Active here is June 09, 2019, 07:10:05 PM

) to see its end. I thank the heavens I am still around and will be to see the end of it
I believe the purpose of this puzzle has been achieved 100% & facts proven to show bitcoin is like the Rock of Gilberta, it can never be moved

That being said, I oblige the OP @saatoshi_rising (and/or whoever that's in charge) to see this fun filled research come to an end in a short while by considering my request, my humble suggestion & plea.
peace & love