As of today, the Sin Squadron's Battleboard shows us holding 18 Squadron Citations. That puts in first place before Lambda (10) and Epsilon (8) on the Squadron Battleboard (the Battleboard also lists the rules for citations).
Let's extend that margin a little bit.

The following battles currently only need one more Sin pilot to fly them to achieve a Citation:

• TIE-TC 1
• TIE-TC 2
• TIE-TC 7
• TIE-TC 9
• TIE-TC 10
• TIE-TC 24
• TIE-TC 25
• TIE-TC 28
• TIE-TC 30
• TIE-TC 33
• TIE-TC 38
• TIE-TC 40
• TIE-TC 44
• TIE-TC 67
• TIE-TC 165
• XvT-TC 2
• XvT-TC 4
• XvT-TC 12
• XvT-TC 13
• XvT-TC 31
• XvT-TC 70
• XvT-TC 76
• XvT-TC 116
• XvT-DB 1
• XWA-TC 5
• XWA-TC 8
• XWA-TC 10
• XWA-TC 13
• XWA-TC 21
• XWA-TC 39

The following battles currently only need two more Sin pilots to fly them to achieve a Citation:

• TIE-TC 5
• TIE-TC 8
• TIE-TC 12
• TIE-TC 13
• TIE-TC 14
• TIE-TC 16
• TIE-TC 18
• TIE-TC 19
• TIE-TC 29
• TIE-TC 32
• TIE-TC 34
• TIE-TC 36
• TIE-TC 41
• TIE-TC 48
• TIE-TC 133
• TIE-TC 168
• TIE-TC 214
• TIE-ID 1
• TIE-CAB 1
• XvT-TC 5
• XvT-TC 6
• XvT-TC 7
• XvT-TC 8
• XvT-TC 9
• XvT-TC 11
• XvT-TC 15
• XvT-TC 16
• XvT-TC 17
• XvT-TC 19
• XvT-TC 20
• XvT-TC 24
• XvT-TC 25
• XvT-TC 59
• XvT-TC 61
• XvT-TC 102
• XvT-TC 111
• XvT-IW 1
• XvT-DB 3
• XvT-DB 11
• XWA-TC 11
• XWA-TC 14
• XWA-TC 15
• XWA-TC 16
• XWA-TC 18
• XWA-TC 19
• XWA-TC 22
• XWA-TC 25
• XWA-TC 26
• XWA-TC 30
• XWA-TC 42
• XWA-TC 43
• XWA-DB 2
• XWA-DB 4
• XWA-DB 5
• XWA-DB 9
• XWA-FCHG 3
• XWA-FCHG 4

• Pilot who completes the most battles: IS-SW
• Pilot who completes the 2nd most battles: IS-BW
• Pilot who completes the 3rd most battles: IS-CW
• First 5 battles completed: ORA