So I am just getting back into riding after a few years off the bike. In the past, all my bikes have had pump pegs, but it seems they are somewhat of a rarity these days. I have always used Zefal HPX full size pumps, which need a peg to stay put.

Do the newer models (Topeak, Park, etc) work without a peg? Or will I still end up having to fashion something out of a zip tie?

Cheers!

They all, including the HPX, work without a peg. They ends are molded to fit the frame tubing.

And I've added a velcro cable tie to the top tube of the bike I use an HPX on. I ride over some pretty crappy asphalt and got tired of having it bounce off.

Been using CO2 on my other bike. I do carry a spare cylinder but haven't needed it yet. So far so good.

mini pump

If you still have your old pump, you should be able to find a Zefal peg clamp thing. It resembles a plastic hose clamp with a pump peg.

If you need a new pump, and understand the advantages of a full size pump, virtually all of them will fit virtually all frames without a peg. For extra tall or extra short bikes the challenge is to find a spot.

I don't have a pic of it (yet) but I mount my new full size pump (I think it's a Park - it's silver) between my front skewer and the bars (next to stem). I have a short bike so it works well. I can ride pretty rough roads at full tilt with no problems (I use 2 velcro straps to hold it in place since the HED skewer isn't ideal for a pump end). I used to carry my Silca like this (with the Campy head, which seems perfect for the old style skewers like Campy's older ones).

I also have minipumps but with bottles, battery pack and ballast (for Down Low Glow), blinkie, saddle bag, all on my very short frame, I'm running out of real estate.

I looked for a way to mount the pump between the saddlebag and the rear skewer (or similar) but couldn't figure out a way. I tried this with the Silca way back when but for whatever reason it didn't work out.

Be creative with placement.

Unless you run tubeless tires and require a huge shot of air to seat your tire/s, I'd use a "forever" pump like a mini/full pump. I'm not a big fan of the CO2. I know, old fashioned. I've used it, carried it, but on a really bad day it can be limiting. (To be fair I only carry two tubes, sometimes three, so it's not like I could make it past 2 flats no matter how I inflated them, but still.)

cdr

I also favor full size pumps due to never running out of air. A few times I've had a slow leak, and rather than change the tube, I've quickly topped it off with the pump a few times to finish the ride.

Another time, I had 3 flats, but 2 tubes. For the 3rd flat, I found some plastic bag litter & wrapped it around the hole 4-5 times. It held air for a week !
I've also bailed out a few riders that ran out of CO2.

I'm fortunate to ride a mid-size frame, so a pump fits nicely under the top tube. The Zefal & Blackburn pumps are nice.
Park makes an adjustable full size pump so it can swap easily from road bike to mtn bike (and has a reversible head).

I just learned a new trick, thanks!

I ride a 56, so finding a pump that fits isnt an issue. It looks as though most of the newer pumps are more rounded and rubberized to grip the tube on the ends. I still have my old Zefal, you just cant kill those things. The Zefal is great, but the "peg" end is not that rounded and made of hard plastic, so it doesnt like to grip that well without a peg.

Oh, and mini pumps are dumb.