Make a pitch for 3 of your ideas that you think have the potential to make the most money. Pitch them to your friends/colleagues/people whose opinion you trust who would be in the market for such a product.
Ask them which one you think is best/most likely to be a product they would use. Tell them it's okay to say none of them. If no one thinks those 3 are good move on to the next.
Comments
"I don't think it's a good idea to work on more than one project", yes I also think that's a bad idea.
Do you want to realize the ideas for fun, for profit or to learn something?
Profit!
Make a pitch for 3 of your ideas that you think have the potential to make the most money. Pitch them to your friends/colleagues/people whose opinion you trust who would be in the market for such a product.
Ask them which one you think is best/most likely to be a product they would use. Tell them it's okay to say none of them. If no one thinks those 3 are good move on to the next.