I always max out my HSA each year and somehow I came up short just over $100 and I thus made a deposit to my HSA from my checking account for that amount (post tax of course) to count towards my 2016 limits. I filled in f1040 Line 25 with that amount and it got me wondering if there's anything analogous for other forms of pretax accounts I can likewise contribute to after the fact?
For instance my retirement account at work contributes pretax, and we have some commuter benefits as well. Is there a way on the 1040 to flesh out some contributions to something along those lines? I like to do this sort of thing when I wind up owing more taxes come this time of year. Seems like Line 32 could be something to take advantage of if I set up my own account and use it for these purposes, but that's assuming I can set on up in 2017 and have it count for 2016 contributions, which I think is allowed up to the cutoff date of Tax Day right?