Grargar: <span class="bold">Humble Weekly Bundle: Retroism</span> PWYW
F-117A Nighthawk Stealth Fighter 2.0
Sid Meier's Pirates! Gold Plus (Classic) $5
Sid Meier's Colonization (Classic)
Sid Meier's Covert Action (Classic)
Sword of the Samurai
All games are DRM-Free+Steam key. In addition, all games also support Mac, except for F-117A Nighthawk Stealth Fighter 2.0, which is Windows-only.
The $5 tier is all games here on GOG that go on sale for ~$1 each; but I think a couple of the lower tier aren't here yet so I'm in for a buck.