A custom tool built in-house.
The current era really overestimates the benefit of using third-party cookie cutter tools. Yes they save on development cost of course. But you're stuck with something that has a million complexities you don't need and that is mostly terrible for everyone. So you pay in an infinite stream of small annoyances which add up.
There's a lot of value in building in-house tools targeted to work exactly like your team works with zero extra complexity.
And look at all the years-and-years-and-years-old jira feature requests that atlassian never bothers to implement and you have to suffer with mediocre workarounds. With an in-house tool you change it in an afternoon to do exactly what you need.
It's not for every company but companies of enough size to support building in-house tools should really give it more consideration.