I've been known to do crimp terminals (e.g., Molex KK, SL) just with needle nose pliers. I don't trust the mechanical result in the least -- I always solder the wire in (using as little solder and time as necessary to wet the wire). Suboptimal, tedious, but useful when you don't have a crimp tool handy.
For higher current connections (up to 10A or so), I tend to go for pluggable terminal blocks, e.g. OSTOQ055450 and OSTTJ055153 (or any other source, Phoenix and Weidmuller being the bigger ones).
Also, SPOX series, very old\\\classic; and uh, I forget what other ones are similar but there's more than a few.
Have seen MTA going flakey, and have migrated them to more reliable connectors too.
Tim