Looking for "all-around" suggestions.

A little less than a year ago, I upgraded to a D5600 from a D3000. It renewed my interest in photography.

I'd like your input on lenses. I have a Sigma 30 1.4 (my favorite), Sigma 150-600 (for birding), and a Sigma 18-300 (for "all-around").

I recently took my 18-300 along to the zoo (my first real outing with it) and I was a little disappointed. I consider myself an amateur and thought that it would fit in between my other two but I feel that it's lacking (budget-friendly, all-around zoom, what did I expect?).

I love the quality of photos from my prime lens. The bokeh, just everything. But for a nice walk-around, I'd like something more versatile (than carrying a bunch of primes). What are your thoughts on the Sigma 50-100 1.8? Do you think it would scratch my itch for something slightly more versatile while giving me more aperture range/low-light capabilities? What are your suggestions? Let's assume I'm shooting mostly wildlife (think zoo or pets, indoors and out), landscapes (I realize 50mm isn't wide, especially on a crop sensor), and occasionally automobiles.

Thank you in advance!

EDIT: I also see the 70-200 2.8 being talked about often. Another possibility? I'd say budget <$2000. Thanks again!

The 70-200 f/2.8 Nikon is an awesome lens.. even the first version (which, if you buy used for around $700, would save you a considerable amount of $$$). Have you considered the Sigma 50-150mm f/2.8 EX? It can be had for around $400 (used), and is quite nice. On your D5600, it will give you a focal range of around 75-225mm equivalent. Also, don't forget the slew of 24-70mm f/2.8 lenses out there, and not to forget the Tamron 28-75 f/2.8 (which is very good, and can be had for peanunts).

Thank you for your input! I should give a 70-200 f/2.8 a chance. I think that could be a very usable focal length (and I wouldn't mind the older version of the lens). I have not considered the Sigma 50-150 f/1.8 (didn't know about it). The idea of an f/1.8 zoom really intrigues me. How do you think it would stack up against the Nikon 70-200 f/2.8? I feel as though the 24-70mm (or the Tamron 28-75) focal length is covered with my Sigma 30 f/1.4. I'm now considering maybe a Sigma 135 f/1.8 prime. I just don't know if it would be versatile for say, trips to the beach or zoo.