The most official list of space group names is probably in the International Tables for Crystallography. But you may find some special things in the PDB that are not in the tables. The latest PDBx/mmCIF dictionary (v5 RC) enumerates all allowed values. That should be all that you can find in PDB:

http://mmcif.wwpdb.org/dictionaries/mmcif_pdbx_v50.dic/Items/_symmetry.space_group_name_H-M.html

"A 1" "A 1 2 1" "A 2" "B 1 1 2" "B 2" "B 2 21 2" "C 1 2 1" "C 1 21 1" "C 2" "C 2 2 2" "C 2 2 21" "C 2(A 112)" "C 21" "C 4 21 2" "F 2 2 2" "F 2 3" "F 4 2 2" "F 4 3 2" "F 41 3 2" "H 3" "H 3 2" "I -4 c 2" "I 1 2 1" "I 1 21 1" "I 2" "I 2 2 2" "I 2 3" "I 21" "I 21 21 21" "I 21 3" "I 4" "I 4 2 2" "I 4 3 2" "I 41" "I 41 2 2" "I 41 3 2" "I 41/a" "P -1" "P 1" "P 1 1 2" "P 1 1 21" "P 1 2 1" "P 1 21 1" "P 1 21/c 1" "P 1 21/n 1" "P 2" "P 2 2 2" "P 2 2 21" "P 2 21 2" "P 2 21 21" "P 2 3" "P 21" "P 21 2 2" "P 21 2 21" "P 21 21 2" "P 21 21 2 A" "P 21 21 21" "P 21 3" "P 21(C)" "P 3" "P 3 1 2" "P 3 2 1" "P 31" "P 31 1 2" "P 31 2 1" "P 32" "P 32 1 2" "P 32 2 1" "P 4" "P 4 2 2" "P 4 21 2" "P 4 3 2" "P 41" "P 41 2 2" "P 41 21 2" "P 41 3 2" "P 42" "P 42 2 2" "P 42 21 2" "P 42 3 2" "P 43" "P 43 2 2" "P 43 21 2" "P 43 3 2" "P 6" "P 6 2 2" "P 61" "P 61 2 2" "P 62" "P 62 2 2" "P 63" "P 63 2 2" "P 64" "P 64 2 2" "P 65" "P 65 2 2" "R 3" "R 3 2"

To get the list of operations you may:

• use a library (cctbx or sglite or another one),
• or use a table (many macromolecular crystallography programs, in particular the ones from CCP4, use a file named symop.lib for it),
• or just use _pdbx_struct_oper_list from your mmCIF file.

Edit: the enumeration vanished from the PDBx/mmCIF v5 dictionary