Sustrans Brochures for the West Coast of Scotland Cyclepaths (all pdfs, so download these links).

Clyde and Loch Lomond Cycleway (NCN 7)
Glasgow to Loch Lomond mainly traffic-free path for cyclists and walkers 20 mls

Lochwinnoch Loop Line (NCN 7)
Paisley to Kilbirnie mainly traffic-free path for cyclists and walkers 14 mls

Hillend Loch Railway Path (NCN 75)
Airdrie to Bathgate mainly traffic-free path for cyclists and walkers 14 mls

Paisley and Clyde Railway Path (NCN 75)
Paisley to Gourock mainly traffic-free path for cyclists and walkers 20 mls

Garnock Valley Cycleway (NCN 7)
Irvine to Kilbirnie 18 mls

Ayrshire Coast Cycleway (NCN 7)
Irvine to Ayr traffic-free route for cyclists and walkers 19 mls

Cunninghame Cycleway (NCN 73)
Kilmarnock to Ardrossan traffic free path for walkers and cyclists 17 mls

Clyde Corridor Cycle Route (NCN 75)
Heart of Glasgow to Uddingston traffic-free walking and cycling route 12 mls

edit one more from the East Coast -
The Esk Valley Cycle Route
Musselburgh to Dalkeith largely traffic-free route 5 mls