For free stuff, the mhak sample packs (there are 500+ free kicks in there iirc) are really nice—at least some of them

sunny lax kick packs

Yup!

And I've heard good things about this one: http://waproduction-samples.com/index.php?route=product/product&product_id=166, although I haven't tried it yet. But to be honest, I haven't checked out new bass drums in a while; between a best-of short list I painstakingly distilled from my collection and the fun I've had with the Nicky Romero KICK plugin, I just haven't needed anything else.

Your example sounds like a pretty basic marimba to me...

You hold a bunch of keys, and the arpeggiator turns them into a riff, based on certain rules. For example, you play B3, E4, G4 and B4, set the arpeggiator to "down", and get the arp from your example. The arpeggiator goes through all the notes currently held, starts at the highest and goes down to the lowest, then repeats. Other modes use other rules, like starting at the bottom or playing random selections from the notes held.

Other, more complex arpeggiators take MIDI files as rule inputs, or allow you to specify note offsets and lengths within their own user interface.

The big game changer for me was learning improvisation. When I was 15-17 I spent most of my free time for about a year or two first learning enough piano to improvise meaningfully (I took lessons for that) and then losing myself in just trying things out, developing a sense of which techniques evoked which emotions, spending untold hours finding pieces – chords, turns of musical phrase – that did something, something specific. I built a musical vocabulary that way, one that loosely translates to emotions. And the foundations I laid then still serve me well now, more than 20 years later. I'm happy that I did this on my own, without deliberately analysing other people's work (at least initially.) It gave me a sense of discovery, and ownership, and made me feel like it was my language, my emotions that I was developing.

As far as "if no one will stay", I gotta reference that classic Field of Dreams: If you build it, they will come.

I've seen it work, and I've seen it fail. I'd be up for hanging out in an official IRC channel, but it's gotta be set up by someone who's in a position of trust (if not actual power) on here. If the people in control of the forum aren't in control of the channel, it doesn't make much sense. Gotta have the endorsement. That also means of course that you gotta have someone on the team who knows their way around the environment and is willing to be at least minimally active there, which might both be hurdles.

I use open headphones for production, but I've got a pair of closed ones too, for when I'm anywhere around other people—open headphones let in the sounds from outside, and they let out the sounds from inside. They're loud enough to disturb anyone in the same room.

This clyp.it site keeps timing out for me.

Can you post a few examples of their kicks and yours?