An alternate way to getting rivens you want without buying or trying to get luck from RNGesus.
Other Warframe Guides:
The Secret of Riven Dedication
Instead of selling your trash rivens try trading them for other rivens it does not hurt to see what other people have and what they are willing to trade for your riven(s). the only downside to doing this is you probably wont get any rivens with good stats you will have to reroll but atleast you will have a chance at the rivens you want for the actual weapons you use.
One last thing to keep in mind rivens have different values and such so there is a chance you may be trading a riven worth 50 plat where the other trading could be giving you a 30 plat worth riven obviously if you could you would just sell the mod and buy it from him so expect to be either.
- Get less than what you gave or...
- Get more than what you gave and of course...
- Sometimes you just have that weapon thats your favorite and gotta make a sacrifice by trading one of your lesser liked rivens like the other person might have to do and call it good.
Example: I traded a silva and aegis riven with bad stats for a really nice war riven. might had been not wise for one of us to do that but the trade had already been passed and we never looked back. And thats what you call dedication to riven mods.