Since Chicago bastard gave you some of the others let's go with team ups with muh boi:
- They have been together in two versions of the "Secret Avengers" namely the versions in 2013/14 by Spencer and 2014/15 by Kot of which I have a huge fondness for the latter and recommend it to anyone who can stomach the comedic tone.
- Secret Empire (2017) and subsequently Tales of Suspense (2017-18) by Spencer and Rosenberg respectively.
- Avengers Assemble by Bendis among others (2012-2014) and later on Avengers by Hickman featured both.
- There was a brief team-up in Thunderbolts 1997-2003 starting with #43 by Nicieza.
The same writer had the team up in Hawkeye (2003/04) #7 -#8.
- Otherwise Natasha made regular appearances in Hawkeye (2012) by Fraction much like Clint showed up on like three brief occasions for Natasha's similarly excellent Edmondson/Noto book (2104/15).
- Then there's Widowmaker (2010) by McCann which was a 5 or so issue mini series between the two of them and mockingbird.
- Last but not least Clint and the Bucksman featured heavily in Kelly Thompson's very recent Black Widow (2020-2022).
Right, sorry if this list is maybe structured weirdly, I've been writing this for the last 30 minutes during program hangups at work.