There are many catalogues offering lists of the best objects to observe outside of Messier’s list. They each have their own strengths and weaknesses and so I have decided to choose from several of them, and split them into seasonal objects.

Choose from

Autumn
Winter
Spring
Summer

Catalogues:

Caldwell (from Patrick Caldwell-Moore)

RASC Finest NGC Objects (Royal Astronomical Society of Canada, Alan Dyer)

SAA 100 (sci.astro.amateur)

SAC 110 (Saguaro Astronomy Club)

The seasonal split is by constellation, as follows:

Autumn

And, Aqr, Ari, Cam, Cas, Cet, Eri, Peg, Per, Scl

Winter

Aur, Cam, CMa, Gem, Mon, Ori, Pup, Tau

Spring

Boo, Com, CVn, CRV, Dra, Hya, Leo, LMi, Lyn, Sex, UMa, Vir

Summer

Aql, Cep, Cyg, Her, Oph, SCT, SCR, Vul