Worst I’ve seen that I’ve later looked up was one offered by me, which is Trilux (player’s two cards + dealer’s up card making a 3 card poker hand) with the following pay table:
Straight Flush: 25:1
3 of a kind: 15:1
On the surface, it may not seem too bad, but when you look into it, true odds of a straight flush are almost 500:1, three of a kind odds are almost 200:1, and so on. This has a 23.2% house edge, so you’re probably better off playing a bad slots game than this bet!