The Sega Mega Drive or Genesis scene is probably the most active as of now with several big commercial titles relesing yearly followed by ton of ROM-only smaller projects and ports released on itch.io. This is largely thanks to the still fairly recent release of the unofficial SGDK development kit making development much more accessible to those not into learning 68k assembler. SGDK itself is still actively developed, releases somewhat regularly and the number of 16-bit Sega game projects keeps growing, as tracked by Pigsy, a developer themself who has taken on porting Castlevania: The Symphony of the Night from the PS1 to the Mega Drive amonh other things.