This is a collection of 4 yellow vintage mostly diecast vehicles.  One is plastic.

Most all have paint loss.

The bottoms were super hard to read but here is the information I did see -

S10 pick up. Stomper USA Schaper. This is a plastic one.

Buddy L Bulldozer, also plastic Made in Hong Kong

Steamroller Majorette

Saab Turbo Matchbox Made in Macau.

These are being offered as a set. No dividual sales.