I play a lot of random city builders and enjoyed most of what’s already listed by others here.

Haven’t seen these ones mentioned yet (I think), but you could check out these to see if any tickle your fancy:

Modern:

• Haven Dock

Prehistoric:

• Dawn of Man

Casual:

• ISLANDERS
• Microtown

Fantasy:

• Founders’ Fortune
• Airborne Kingdom
• The Wandering Village
• Fabledom
• Noble Fates

Medieval:

• dotAGE
• Foundation
• Going Medieval
• Farthest Frontier
• Kingdoms Reborn
• Settlement Survival
• Clanfolk

Sci-fi:

• Cliff Empire
• Space Haven
• IXION
• Stranded: Alien Dawn