[gilleain]

A very reasonable question, that I don't have an immediate concrete answer to!

Apparently I upvoted this question in the past (found it by searching for an answer - no AI, like the good old days)

https://biology.stackexchange.com/questions/2507/are-there-a...

One answer mentions actin and hexokinase. I'm not familiar with the actin fold, but looks like a bab sandwich of some kind.

Another commenter on this page mentioned the 'Rossman fold', another classic, and TIM barrels also occur to me. One caution is that some of these I would consider higher-level patterns - the 'Topology' level of CATH hierarchy.

Naturally, the more high-level (abstract) the fold pattern, the larger the sequence space it covers. It is less interesting to say that a helical bundle (for example) covers a lot of diverse sequences.