Which are the five manga series that are based off the Toaru Majutsu no Index franchise?

Question

According to Toaru Kagaku no Accelerator

Toaru Kagaku no Accelerator (とある科学の一方通行アクセラレータ Toaru Kagaku no Ippō Tsūkō?, lit., A Certain Scientific Accelerator) is the fifth manga series that is based off the Toaru Majutsu no Index franchise

Which are them? Aside of Toaru Kagaku no Accelerator and Toaru Kagaku no Railgun?

Answer 1

The list of manga series page on the Toaru wikia may be helpful. Going strictly by chronological order by date of first publication, the manga order would be:

1. Railgun (Feb 2007)
2. Index (Apr 2007)
3. Endymion (Feb 2013)
4. Index-san (Sep 2013)
5. Accelerator (Dec 2013)
6. Heavy (Feb 2015)
7. Idol-sama (Oct 2015)
8. Astral Buddy (Apr 2017)
9. Virtual-On (Dec 2017)

All the Toaru manga series can be divided into several different categories:

• Main series: These contain canon storylines. I bolded the main series titles in the list above. The Index manga is an adaptation of the original light novels. Railgun, Accelerator, and Astral Buddy are original storylines written by Kamachi Kazuma.
• 4-koma series: Fun silly spinoff manga, similar to what Rock Lee's Springtime of Youth is for Naruto or what Haruhi-chan is for Haruhi Suzumiya. This includes Toaru Majutsu no Index-san and Toaru Idol no Accelerator-sama.
• Special stories: One-off stories. Usually short, usually for an anniversary event or something like that. Endymion is canon, but I'm not sure about the others.
• Anthology manga: Sort of like a doujinshi collection, except it's official. Content is non-canon. Lots of different mangaka come together and contribute a one-shot to the anthology. (This happens with lots of other series, too).