There is one more Rin missing from this picture and she's from the Fate series.

also kokonoe_rin is missing

...and Tezuka Rin from Katawa Shoujo
...and Rin from Naruto, despite being dead
...and Rin from Yu-gi-oh! Arc-V
...and few other Rins.

sammyG said:

There is one more Rin missing from this picture and she's from the Fate series.

iggikoopa said:

also kokonoe_rin is missing

These two pictures should answer the questions. The first picture is about characters whose name end with 凛 but Shimotsuki Rin (霜月 凛) is missing. The second picture is about characters whose name end with りん and its various forms such as リン.