For a while now I’ve turned to inexpensive film made in China to experiment on. These tended to be Shanghai GP3 and Lucky SHD100. Both iso 100 films, both could be problematic at times but their low price made them very appealing for not-so-critical, fun photography. Both were (are?) made in 35mm and 120 with Shanghai also having a 4×5 and bulk 35mm products.
Lately it’s been hard to find. There’s still some on Ebay but it’s price has gone up considerably, around