Eamonn Ansboro has been a keen observer of TNOs and John Saxton has measured a rotational lightcurve too.
The orbits of the brighter ones are well tied down and very few bright ones are discovered.
I’ve done the latest list for the 2022 Handbook and since 2014 only one bright TNO in the Top 25 has been found, namely 2018 VG18.
Of course the most effective thing that amateurs can do is to observe stellar occultations by TNOs.
Richard