There are a very few opportunities for +EV play without bonuses. Many Playtech casinos offer blackjack switch, which has a HA of 0.05%. They give 0.1% of your wagers back as comps, so net is a 0.05% player advantage. That means for every $1000 you bet, you should win 50 cents.

Some casinos also offer single-deck blackjack, which can be beaten without counting by playing optimal strategy. Player advantage is 0.14%. Understandably, the casinos don't offer comps for playing this game.

These aren't really exploitable opportunities, because the edge is so small relative to the variance. I'm sure if you sit down and start grinding it out at single-deck bj for 8 hours a day, or write a bot to do it 24 hours a day, you'll get banned pretty quick.