I also have a 12 qt. Igloo Quantum cooler. It’s made to hold 1 liter bottles standing up. It’s small and square shaped with 2 cup holders on top. It’s decent if you pre-chill the inside overnight.

 

 

Yeti Roadie. Pretty small footprint and keeps everything nice and cold with a couple ice packs.

i cant resist ?

here is mine, a gift from my son in law. i’ve been throwing the bling to it whenever i can find a cool sticker. i’ll put it in the Javelin every now and then but my built ins work just fine. better on the job or out by the pool....for my sweet tea.

My stratos has a built in cooler but I just use it for storage. It holds ice pretty good but I prefer bringing my cooler. I have an Engel 19 qt. It's perfect for just me to bring water and some snacks. I fish alone majority of the time so it is perfect for me. When other come along I either tell them to bring their own small cooler or just downsize on my stuff. The cooler holds ice for several days.

"Coleman Super Oscar"

 

I was going to suggest the standard Lil Oscar 8 quart/six pack size. I have two that I've regularly used since the early '80s. Fold the handle down and you can sit or stand on them. All you have to do is look at the number that have survived to tell how well built they are. Here's one...

 

www.ebay.com/i/382225441558?chn=ps

 

 

I have an Eagle Talon Yak by Field and Stream.  A milk crate doesn't fit in the rear space, but my Igloo Marine cooler fits.  It keeps ice cold on the water.  I use it for fish when panfishing, and can keep water, apples, bars, or whatever in a plastic bag inside.  I have attached rod holders similar to Catt's photo.  I usually never get to fish more than 6 hrs, so it is fine even in the MS heat.  I attach with bungee cords.