Side Bets
As far as Basic Strategy goes, these side bets all have enormous house edges.
Some are subject to (specialized) Card Counting techniques.
The best is The "Over - Under" but that has been relegated to the dustbin of B J history, and where it existed it had an absurdly low limit (since it was easy to beat)
Blackjack Switch is offered downtown for low stakes -- and THAT is a sweet game as the house edge when using the Specialized Basic Strategy derived by Arnold Snyder in the "Big Book of Blackjack" is only -.25 % so it is easy to beat with card counting.