Here is the basic 1-3-6-2-5-1 progression with a few alterations. I plan to practice this in every key.
EX1 The basic progression
C/CEG
E/EGB
A/ACE
D/DFA
G/GBD
C/CEG
Ex2 Using realative majors
C/CEG
E/BDG.............G is the relative major of E
A/CEG
D/CFA
G/DFBb
C/EGC
Ex3 Using 5 of 5 tritone substitute
C/DbF#Bb...........F# is the tritone sub of C
E/DFBb
A/EbGBb
D/CEbAb
G/DbFAb
C/CEG
Ex4 Using Major 2nds
C/DF#A............D is the 2 chord of C but I'm making it major.
E/DF#Bb
A/EbF#B
D/EAbB
G/EADb
C/EGC
mysteryman