Welcome from the uppity mountains of central California! Ah, so you want lens advice? This is the right place! Let me tell you how I've accumulated ~225 lenses -- and sold off 110 more, to help pay for the keepers. How? I deal lenses on eBay. Buy real cheap, sell for not quite so cheap, to buy yet more stuff. It's easy! But I digress.
I see rational lens accumulation as coming in 3 stages:
1) Coverage. My Tamron 10-24, DA18-250, and Sigma 170-500 certainly cover the focal-length range. With help from a F35-70.
2) Speed. The FA50/1.4 is my
gotta-get-the-shot lens. And I have fairly cheap fast f/2 manual primes at 24-28-35-58-85mm.
3) Character and specialties. Fisheyes, macro lenses, an enlarger zoom, and various slower lenses just make different images.
4) Mania. OK, I cheated. I like really cheap enlarger-copy-projector-process-Xray-scavenged lenses giving unique results.
A good way to manage lens purchases is to ask yourself: What do I want to do that I can't do with what I have? The answers may lead you to ultrawides and fisheyes, or long telephotos, or macros, or very high-speed lenses (wide maximum aperture), or lenses deemed excellent for portraits, etc. Budget may drive you to used lenses. Here are some tips:
https://www.pentaxforums.com/forums/pentax-lens-articles/59245-pawnshop-lense...ers-guide.html
But the best way to start is just to GET OUT AND SHOOT! Use what you have, use it constantly, learn its strengths and weaknesses. And learn what focal lengths you like best -- and where you feel limited by the 16-45's reach.
Here's an exercise in seeing: Every week, scotch-tape your 16-45 to one focal length: 20mm, 25mm, 30mm, 35mm. Shoot at only that focal length for a week. Each focal length (and each lens!) is its own window on the world. Become accustomed to each window. I've spent months shooting with only a 28mm or 55mm lens. Working that way makes me concentrate on angles and distances.
Most of all: Have fun!