I use backings to practise quite often but many of them get tedious after a while, especially the ones made in Band-in-a-Box or the iReal Book. Sure, there's the Aebersold playalongs and the Hal Leonard ones but these often feature piano comping and sometimes you just want to hear something different to play along with. These days I kind of prefer duo and especially drummerless trio settings for playing in anyway. A while ago I came across the Youtube channel of Mr. Sunny Bass. He's double bass player from Italy that has over 170 videos featuring jazz standards on double bass to play along with. Click on the playlist icon in the left upper corner in the vid below to view it.
I added some examples of me improvising over a few standards. As you can hear, I sometimes add a comping guitar to create my own backing track so I can play with a "trio" feel. They also work great for practising duo playing with bass of course. Anyway, I have to thank the guy for all his hard work and judging from the reactions under his videos and the number of subscribers, many people dig them.