
NEMO
Disco 15 Series
Spacious for side sleepers; bulky, temp rating optimistic.

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I have the Teton Celsius XXL 0degree bag and it's amazing. I camped last November and it went down to 25 degrees and I was toasty warm! It comes with a stuff sack and packs down pretty small for how big it is. I love it! I'm a side sleeper and it gives me plenty of room. I just bought a second one for my son :) https://www.amazon.com/gp/aw/d/B005EPRFF4?psc=1&ref=ppx_pop_mob_b_asin_title
Yeeeessss, I just bought another for my son who outgrew his ozark trail kids mummy bag. It's so warm and ours are the XXL so super spacious. I also use mine as a blanket in the summer months. Last night we got down to 52 but we were perfectly comfortable!
As long as you're not hiking and your car camping I would suggest Teton Sports zero degree XXL sleeping bag.
I have this bag (0F) and it's very comfortable. Just camped in Colorado at 8,200 feet, got down to high teens/low 20's, and I was toasty warm. I did not need a blanket, the bag was enough.
We use Teton Celsius 0F bags for camping in cooler temps - they come in 20F, 0F, and -25F versions. It looks like their regular mummy bags are also available in 0F if you don't want to shell out for the down version. They're on sale right now. With that and a properly rated pad, you should be comfy. You can always add blankets and clothing layers as well.
Teton Celcius XXL, there is so much room in there. I'm a big dude and I roll in it easy.
Second the Teton Celsius XXL! I grabbed one a couple years back for a week-long trip and it was a game changer for both warmth and comfort. I’m a side sleeper too and being able to move around inside the bag made sleeping way easier than those tight mummy bags.

NEMO
Disco 15 Series
Spacious for side sleepers; bulky, temp rating optimistic.
Hammock Gear
Classic Burrow 20°F
Budget king; very warm but heavier than ultralight.

NEMO
Disco 30
Spoon shape for side sleepers; prone to zipper issues.

Western Mountaineering
VersaLite
Durable, very warm; premium price, too hot in summer.

Katabatic Gear
Alsek 22°F Quilt
Versatile 3-season quilt; secure pad attachment, high price.

Ranked #1
NEMO - Disco 15 Series

Ranked #1
Kelty - Tru.Comfort Doublewide 20
Ranked #1
Enlightened Equipment - Revelation APEX

Ranked #1
NEMO - Disco 15 Series

Ranked #1
Feathered Friends - Egret UL 20/30

Ranked #1
NEMO - Disco 15 Series