Toradora!: SOS! Kuishinbou Banbanzai

Both are turned into character chibis and have the similar chibi fun, if it helps any, both the voice actors for Taiga and Shana are the same! 

Short and funny chibi specials. 

Both are drawn in the "chibi" form. Both are funny and short! If you liked one, you'll like the other! 

Both are short, and talk about food 

In both of them we have characters from main series in Chibi version. Also humour is similar. 

Both are spin-offs of their respective original series that poke fun at characters and where the characters are chibi-fied. 

Comic reliefs for respective series. K-ON doesn't really need comic reliefs though. Purpose of these short bonuses are nothing short than boosting DVD sales, that sound like a similarity an adult may talk about. 

funny SD/Chibi characters specials. 

Similar feeling and humour, both of them are from J.C.Staff. Also chibi Minorin with flower on her head remainds me of Potemayo. 

Same Chibi and humour stuffs.