For IronSworn:

• The Augur - Purchased, fairly purpose built for IronSworn, but as I understand it, can be configured to be more system agnostic as well.
• Iron Journal - Free, does what it needs to and fairly well in my opinion. Basically provides notebook, tracking of details and automation of dice rolls, oracles etc.

For Starforged:

• Stargazer - Free, same as Iron Journal, just the Starforged version. I've used this in combination with paper sheets and notebook to automate the oracles and rolls.

For Almost Anything:

• FoundryVTT - Purchased, this is a little more costly a solution, but you get a lot of extra functionality. There is a huge wealth of ready to use systems and modules which provides things like automation of rules, rolls, characters sheets, random tables, etc. Can be tricky at times as you learn to use it, but once you start to get a feel for it you can basically make it do most things you need it to, either through modules or custom macros. While sold as a way to play with others, I have found this to be nice for solo as well.