I think you're talking about the tank-top style that kind of "wraps" in the back? I've never made one (very common in toddler patterns IIRC) ....
If you're just looking for an easy top which doesn't have buttons/zippers, peasant blouses are very quick and easy -- I think the pattern I use is a New Look one. Front, back, and arm pieces are all it takes. OR, you can make a plain cotton tank-top (doesn't have to be knit fabric), which just pulls over the head pretty easily too. Or, there are the peasant style blouses with the longer sleeves and placket in the front and ties (no elastic gathers) ... might be more complex than what you're looking for?
those sound a little more than what I was thinking. Thank you though.
I'm trying to work thru my stash by making simple little things for my kids. My dd is 4 so she's a good size for most of the fabric peices I have left. I just thought of those shirts and thought I'd attempt one.
Is this what you are talking about? I make one of those toddler dresses but it has buttons, but would be easy to modify the pattern to leave them out... here is a idea of what the crossover back looks like.
I have made several of those tanks also and they are almost as easy to make and can be much more useful if you go ahead and make them reversible. I usually make the tank reversible (it helps to hide the seams) and make a matching skirt out of the two fabrics in the tank. You make two pieces the same and them stitch them all together except for the shoulders, the shoulder seams are the last and I usually finish them with some kind of decorative stitch.
Hope this helps