DBS has some doggies on bikes that are cute. I did them for my sons-in law who are bikers.

Yes, if you want motorbikes in cartoon, real looking (coloured) as well as redwork & they also do a set every year for "Biker's Week" they call it. That is DBS (designsbysick.com) sometimes they have good specials going too.
Also, have you looked at Annthegran.com ? she has a few freebies of all sorts of things, you might find something there too. If I think of any other places I'll let you know. I do know of one that has that Crazy lady that is done up in nursing, housewife, etc. on a site, but can't think if they had any of her with bikes. Sorry I can't help much more.
You could also look up on different sites under "Tribal Designs", quite often those interlock with biker's art, etc.... even a bit of Celtic.
Have fun looking, I hope you find what you are looking for, & hope you have a great New Year.
Reggie

SICK has all of their designs on sale right now! I have one of their Biker sets. My next door neighbor will see me struggling to get the groceries out of the car and up the steps and will walk over and help me sometimes. He has a Harley sitting next to his big red Surburban in his drive and keeps it very shiny. I embroidered him a design that looks very much like his Bike by changing the colors on a sweatshirt last Christmas and this Christmas, I got him an authenic Harley sweater. He is a few yrs younger than my son and just as immature when it comes to his "toys"! Two of his four daughters are now in college and he has just had to buy one of them a new car so it has put a bit of a crunch in his toy buying. He works for Delta and has for 19 yrs so he makes good BUT the oldest daughter is in Ga.Tech College $$$$$$ and the next in line is in a smaller college. He will have another one in college next year so he had had to tighten his budget a bit! NOT so many toys...heehee I guess they all have to grow up sometimes. I have had some of their designs that did not sew out well but the bike turned out great.