Good thing you've put this into the general category so all ranges are on the table. Difficult choice whether it's worth including engines you've only seen pictures of. I've settled with engines that I own.
1: Confused Thomas from Thomas and Freight Cars Set (lovely face and one of the few Motor Road and Rail releases of Thomas with a white running board.)
2: Sir Handel (TrackMaster by Fisher-Price version) (aesthetically pleasing engine with a nice shape and good likeness of Sir Handel, plus so shiny.)
3: Percy and Rocky (A well-known face captured so well, plus some bonus crane interactivity. What's not to love?)
4: Edward (2012-2014 TrackMaster by Fisher-Price version) (The face just pops, a lot of wheels even if some don't touch the track, and a nice looking engine when it runs, even if the tender looks a bit too far apart)
5: Gator and Marion (An unique shiny looking engine, plus the bonus of a moving steamshovel and a fitting little rock truck can perfectly blend in with Marion's shovel. Plus all pieces look visually appealing on their own or all together.)
1: Confused Thomas from Thomas and Freight Cars Set (lovely face and one of the few Motor Road and Rail releases of Thomas with a white running board.)
2: Sir Handel (TrackMaster by Fisher-Price version) (aesthetically pleasing engine with a nice shape and good likeness of Sir Handel, plus so shiny.)
3: Percy and Rocky (A well-known face captured so well, plus some bonus crane interactivity. What's not to love?)
4: Edward (2012-2014 TrackMaster by Fisher-Price version) (The face just pops, a lot of wheels even if some don't touch the track, and a nice looking engine when it runs, even if the tender looks a bit too far apart)
5: Gator and Marion (An unique shiny looking engine, plus the bonus of a moving steamshovel and a fitting little rock truck can perfectly blend in with Marion's shovel. Plus all pieces look visually appealing on their own or all together.)