I really like Dragons in general, Eragon was the series that really got me into fantasy as a genre so they have a soft spot for me. I do really like what we've gotten from them in the cosmere so far and I'm excited to see more!
Wayne is my favorite character in era two of mistborn (really close with steris in book 4) but wayne is the most enjoyable across the whole saga for me
Gold compounding is by far my favorite, so many of the characters I like in superhero media are the ones with healing factors (wolverine, deadpool) and the execution scene of Miles hundredlives is one of my favorite scenes in mistborn. It's absolutely horrifying watching the healing slowly peter out.
The two more scholarly orders are the ones I gravitate towards, those being Truthwatcher and Elsecaller. Truthwatcher edges out a bit more for me, enough that I have the Truthwatcher keychain charms and socks lol. I think Regrowth is my favorite of the surges as it seems the most widely useful in a societal application, but I think it would have been interesting if Regrowth and Division were next to each other instead of having Abrasion between them. The duality of destruction and healing could have made for an interesting order. But of the base orders I think Truthwatchers would be my favorite, for the same reasons as earlier with Regrowth but I really want to see more with how the Truthwatchers interact with Illumination, especially in the higher ideals where solid lightweaving becomes feasible.