Just to contribute - although I'm not a "classical" player, I like to use etudes from the classical repertoire to stretch my technique (which needs a lot of stretching at this point
)
I found the well-known Sor Study in B minor (Opus 35 #22) to be pretty helpful for barre chord study. Some full B minor and F# major bars, some moving back and forth between the two, many partial bars (and discovering where I didn't need a full bar was useful), and enough non-bar stuff in between to rest your hand.
Your mileage may vary, but I found I learned a lot working on this - at first, I couldn't play it, now I can.
Recently I've been working on Carcassi Op 60 #3. Some tricky partial bars, and some interesting bars that ask you to put the 4th finger one fret higher than you'd expect in a bar (I hope that makes sense, see measure 7 and measure 14 for instance). I'd run into this in an arrangement of the Beatles "Because" and Fleetwood Mac's "Never Going Back Again" and I find myself more capable of working on those, probably due to the practice in the etude. It's tricky keeping the bar on the 1st finger while stretching out to get the 4th finger up...
And the etudes are good music, in a classical way, so they're pretty to work on.
I hope this idea helps!