Comments on https://lichess.org/@/prostheticbrain/blog/a-rare-scotch-game-variation-the-schemm-variation/Je4DO9HI
4...Bc5 is about as popular as 4...Nf6.
Another interesting move is the Steinitz Variation 4...Qh4. It wins a pawn by force, but white gets good compensation.
Nxc6 followed by xd5 promises white qn easy advantage...