Potentially maxed and maxable levels in N++ as of Jan 2019.

MAXED LEVELS (with at least 20 ties for 0th)

SI-C-00-01
SI-B-01-02
SI-B-01-04
SI-C-01-04
SI-A-02-01
SI-A-02-02
SI-A-02-03
SI-B-04-01
SI-E-04-00
S-B-02-02
S-C-05-00
S-C-05-02
S-A-07-03
S-B-08-02
S-C-09-01
S-D-10-03
S-B-11-00
S-B-15-01
S-A-17-01
S-A-18-00
SL-A-00-00
SL-A-01-02
SL-A-07-01
SL-A-13-01
SU-A-03-01
SU-D-04-03
SU-A-05-02
SU-C-05-01
SU-B-15-04
SU-X-06-01

MAXABLE LEVELS (most number of ties for 0th):

SI-C-04-01 (14)
SU-C-08-02 (14)
S-A-05-01 (13)
S-C-12-01 (13)
S-X-02-00 (13)
SU-X-06-03 (13)
S-B-00-00 (11)
S-A-13-04 (10)
!-C-09 (10)
SI-D-02-02 (9)
SU-B-01-00 (9)
SI-E-00-02 (8)
SI-E-02-01 (8)
SU-A-06-03 (8)
S-C-07-00 (7)
SI-C-01-01 (6)
S-A-15-01 (6)
S-C-19-02 (6)
SL-D-09-02 (6)
SL-A-14-03 (6)
SI-E-01-00 (5)
SI-B-04-00 (5)
SL-E-00-04 (5)
SU-A-06-01 (5)
SU-B-07-01 (5)
SI-B-00-04 (4)
SI-C-01-00 (4)
SI-E-03-00 (4)
SI-B-04-04 (4)
S-A-10-01 (4)
S-B-15-04 (4)
S-E-16-03 (4)
SL-B-08-01 (4)
SU-A-08-00 (4)