Assuming the garage door is steel, dry, clean and abraded prior to application we can recommend Rust-Oleum CombiColor Original.

This is available in many Ral and BS colours in a satin or gloss finish.

If the door is galvanised or aluminium we recommend spot priming bare areas with Rust-Oleum 3302 CombiPrimer Adhesion prior to application.

If the door is timber we can recommend Rust-Oleum CombiColor Multi-Surface.