We tested quite some different miRNa and snRNa and using normalizing tool (like G-norm) then decided, which are the most stable small RNA that we can use for specific experiment. I do not suggest to use only one normalizer but more, as the small nc or miRNAs can act 'weird' (by weird I mean very non predictable) depending on the tissue, cell culture. If you are using Taqman probes (or not), here is a decent list of different sn RNAs and miRNAs that could be potential good endogenous controls: https://tools.thermofisher.com/content/sfs/brochures/cms_044972.pdf
Thank you Strazisar. Another thing if you know. I read that I can avoid that "weird" part by using a spike-in control to avoid variability. Do you have any experience with that?