The only creatures that avoid Flame Sweep’s damage are those you control with flying. The set of creatures dealt damage includes creatures you don’t control with flying and creatures you control without flying.
Lovlighet:
Standard: Ikke lovlig
Pioneer: Lovlig
Modern: Lovlig
Legacy: Lovlig
Vintage: Lovlig
EDH / Commander: Lovlig
Pauper: Ikke lovlig
Explorer: Lovlig
Historic: Lovlig
Brawl: Ikke lovlig
Premodern: Ikke lovlig
93/94: Ikke lovlig