Leg structures:
Normal/Elimination Legs
Non-elimination Legs
Double-length Legs
Keep Racing Legs
Final 3 Legs (includes the Final 3 non-eliminations)
Tasks & Markers:
Legs Without a Detour
Legs Without a Roadblock
Legs With 2 Roadblocks
Legs With a Fast Forward
Legs With a Speed Bump
Legs With a Route Info Task (I'm not sure with this one)
Legs With an Intersection
Legs With a Yield
Legs With a U-Turn (separate (?) from Double U-Turn, Blind U-Turn, and Blind Double U-Turn)
Legs With a Switchback
Locations:
Legs on 1 Country
Legs on 2 Countries (usual legs, e.g. Leg 1: United States > Chile)
Legs on 3 or More Countries
Legs that Visited Territories (defined as either geographically distant (e.g. French Polynesia) or geopolitically separate (e.g. Hong Kong))
Others:
Self-Driving Legs
Night Legs (there isn't an HoO where teams had to wait for morning)
Legs With Double Eliminations (2 teams eliminated on the same leg)
On route distances, maybe you could use ranges (e.g. 50 km - 100 km). Also, I don't think you should categorize what type the tasks are, since a lot of them are hybrids...