There are quite a few. Check it out on Aliexpress for instance. Mxus, Bafang, Mac and many others all make Hubmotors that will fit into 135mm dropouts. Just remember, they will work better with a non suspension front fork, and also fit some good Torque Arms.
Personally, I think you would be better advised to fit a rear Hubmotor. I believe you will find the bike's handling and balance much nicer with a rear hub, and then it will be much easier to use a front suspension fork if you choose later.