Index's Best Pair poll from 2013
1st: Touma Kamijou & Mikoto Misaka - 932 votes
2nd: Touma Kamijou & Accelerator - 781 votes
3rd: Accelerator & Last Order - 411 votes
4th: Touma Kamijou & Index - 215 votes
5th: Mikoto Misaka & Accelerator 213 votes
6th: Index & Mikoto Misaka - 176 votes
7th: Mikoto Misaka & Last Order - 159 votes
8th : Index & Last Order - 100 votes
9th: Mikoto Misaka & Misaka Sister - 98 votes
10th: Mikoto Misaka & Kuroko Shirai - 86 votes
11th: Accelerator & Musujime Awaki - 72 votes
12th: Accelerator & Tsuchimikado Motoharu - 69 votes
13th : Index & Accelerator - 61 votes
14th: - 49 votes
Laura & Aleister
Kanzaki Kaori & Misaka Mikoto
16th: Index & Stiyl - 46 votes
17th: Misaka Sister & Accelerator - 45 votes
18th: - 42 votes
Kamijou Touma & Kanzaki Kaori
Shirai Kuroko & Musujime Awaki
Index & Kanzaki Kaori
21st: Misaka Sister & Last Order - 37 votes
22nd: Kamijou Touma & Aleister - 32 votes
23rd: - 31 votes
Tsuchimikado Motoharu & Tsuchimikado Maika
Touma Kamijou & Tsuchimikado Motoharu
25th: Misaka Sister & Shirai Kuroko - 29 votes
26th: Touma Kamijou & Misaka Sister - 28 votes
27th: - 27 votes
Kaori Kanzaki & Accelerator
Kaori Kanzaki & Motoharu Tsuchimikado
29th: - 26 votes
Touma Kamijou & Aisa Himegami
Accelerator & Aogami Pierce
(It’s seems to have the votes in this channel recently so I decided to share this ancient poll again)
Source: https://kamo2kamo.com/toaru-rankcomic/