Carpenter Brut and Perturbator are amongst my favorite artists. OG French synthwave projects along with Kavinsky, but darker and more aggressive than most.

Mega Drive is always a safe bet, along with Dance with the Dead, Laserpunk or DEADLIFE.

For a more '80s-pop sound, you might enjoy Fury Weekend.

Not synthwave by very adjacent, I'm a huge fan of Master Boot Record and Keygen Church (same guy), but it's more metal but played by a SoondBlaster 16 sound card from the '90s.