It's all in the title, folks.
What Are Some Bombs That Pair Well With Swords?
Any bomb that reduces enemy speed.
Haze, and vortexes do this and so do some Shard and Blast bombs
I have a detailed sword guide that you may find useful. See the Mixing Weapon Types section for advice on bombs to pair with swords. It ends up being what the other posters have already said.
vortex, (does better with heavy and medium speed weps, fast ones do ok with it)
1. Elec Vortex
2. Obsi Crusher
3. Gravi Vortex
4. Venom Veiler
5. Voltaic Tempest
6. Stagger Storm
7. Shivermist Buster
Vortex and haze bombs work great with anything, swords included.
Shivermist and calibur type weapons
Vortex with the cutter type swords
And a bunch of other combos that I probably can't think of.
Vortex and Brandish seems to be a nice combination in my personal experience, since Vortex groups enemies together in wich time (With about medium ctr) you can charge your brandish and unleash a charge attack on a lot of enemies at once...
brandish and vortex.
sealed line and vortex.
cutters and vortex.
seriously, get a vortex. although know that your teammates will be way happier than you when you use it. it takes a bit to get used to the charging movement speed of the vortex lines, and overall when you bring a vortex it's better to have someone else do the killing. not that you can't use it solo, it's just way more effective when you're not.
algorithms are the solutions to any problem.
By the way, you might want to look up "Halting problem" on Wikipedia. ;)
Best hands down is any vortex line.
Next would be Haze.
Then Blast.
Then shard.
My personal recommendation is the Electron Vortex. Its worth the effort to get.