What kind of music do you like? Are you looking for sounds that you've heard in classic Mellotron music or something completely different? Remember that not all Trons sound alike, so any sample recording you hear may not sound exactly like it will on your Tron.
You can listen to the Memotron example of 24 of the sounds that are available from Streetly, bearing in mind that they were recorded from the output of a perfectly maintained Tron.
No matter which sounds you choose, I recommend the tuned tapes. I was against them in the beginning, but since I've owned about 40 of them over the last several years, I wouldn't have them any other way.
By the way, what kind of condition is your Tron in? Sticky tapes could also be due to keyboard adjustment. I would start there before taking a chance on ruining a new set of tapes.