Mods is a game in and of it self, if you have a base of all mods in your inventory have base 10 speed, you have many options.
Take a hard look at your gold mods. Any color below that, that has the same speed is "worth more"/has more potential. Look at the other secondaries sell the less useful ones, slice other ones up to gold, rinse and repeat.
The only way to know if the mods in your in box are junk is to work through them. Even with all base 10 speed, you have mods that are worse than others. The only way to find 20+ speed mods is to keep working through mods.