Will we ever run out of INT rules?
There are 2^102 INT rules. Not counting those which have B0, B1c, B1e, or B2a, there are 2^98 of them. Using the constraints in LaundryPizza's post
here, 3/4 of non-relativistic rules can expand their bounding box (has B2c, B3i, or both), and another 3/4 still can expand their bounding diamond (has B2e, B3a, or both), and 1/4096 of these rules do not have spaceships as all patterns cannot shrink (giving a total of 4095/4096 rules where some patterns can shrink their bounding dimensions). Hence there are a total of about 3/4*3/4*4095/4096*2^98 = 178219844327588632935184465920 theoretically-spaceship-supporting rules. This is, of course, a very simplistic estimate, and there are far more parameters to consider, but this is only a small thought experiment, so let us assume that 1/16 of these rules = 11138740270474289558449029120, or approximately 1.11e28 rules are interesting.
There are about 180000 posts on the forums, and at the time of writing the forums has existed for 5567 days. This gives a total of about 32-and-a-third posts a day.
This gives a total of 344497121767246068818011210 (rounded-up) days for the forums to have one post each about an 'interesting' INT rule, and 1722485608836230344090056050 days to have 5 posts about each 'interesting' INT rule, or about 340 trillion Universe lifetimes. This is not counting - well, practically, everything else.
So, the short answer is no, we will never run out of INT rules. For the time being. Unless a sentient supercomputer posts 10 quintillion posts a day, five posts each on a different INT rule each time.
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This is a prediction page by me:
https://conwaylife.com/wiki/User:H._H._ ... yLife_2050
Edit it if you want to!