The red and the black: lumbejack plaid
background: conic-gradient(transparent 25%, #e72e33 0% 50%, transparent 0% 75%, #020202 0%) 0/ 4em 4em, repeating-linear-gradient(45deg, #020202 0 2.83px, #e72e33 0 5.66px)
Patterns created with CSS gradients. No other images used and they are all tiny! All of them are under 500 bytes minified, some of them well under!
background: conic-gradient(transparent 25%, #e72e33 0% 50%, transparent 0% 75%, #020202 0%) 0/ 4em 4em, repeating-linear-gradient(45deg, #020202 0 2.83px, #e72e33 0 5.66px)
background: conic-gradient(transparent 25%, #d2e5b7 0% 50%, transparent 0% 75%, #79598b 0%) 0/ 4em 4em, repeating-linear-gradient(45deg, hsla(278, 21%, 47%, .3) 0 1px, #d2e5b7 0 2.83px) #d2e5b7
background: conic-gradient(at 75% 75%, transparent 25%, #f0efea 0% 50%, transparent 0% 75%, #3c517c 0%) 0/ 2em 2em, repeating-linear-gradient(45deg, #3c517c 0 1.41px, #f0efea 0 2.83px)
background: repeating-conic-gradient(from 30deg, #afe9dd 0% 120deg, #9bc3bb 0% 50%) 0/ 4em 6.928em
--l: transparent 49%, #fdfdfd 50%, transparent 51%;background: linear-gradient(56deg, var(--l)), linear-gradient(-56deg, var(--l)), repeating-conic-gradient(from 34deg, #b5191d 0% 112deg, #e1d9a8 0% 50%) 2.237em 0;background-size: 4.474em 6.632em
--l: transparent 49%, hsla(0, 0%, 100%, .5) 50%, transparent 51%;--s: / 3.632em 7.128em;background: linear-gradient(63deg, var(--l)) 0 var(--s), linear-gradient(-63deg, var(--l)) 0 var(--s), repeating-conic-gradient(from 27deg, #93b4c5 0% 126deg, transparent 0% 50%) 1.816em var(--s), linear-gradient(90deg, #b43129 50%, #596c7b 0%) 1.816em/ 7.264em
--l: transparent 49%, #fff 50%, transparent 51%;--s: / 4em 6.928em;background: linear-gradient(60deg, var(--l)) 0 var(--s), linear-gradient(-60deg, var(--l)) 0 var(--s), repeating-conic-gradient(from 30deg, #d6cdac 0% 120deg, transparent 0% 50%) 2em var(--s), repeating-conic-gradient(#9cb3bb 0% 25%, #9cb08b 0% 50%) 2em/ 8em 13.856em
background: repeating-conic-gradient(from 45deg, #588333 0% 25%, transparent 0% 50%) 0 2em, conic-gradient(#6d983f 135deg, #c3d87d 0% 225deg, #79ab4a 0%);background-size: 4em 4em
--l: 25%, transparent 0;background: conic-gradient(at 80px 20px, #fff var(--l)) 20px 80px, conic-gradient(at 60px 40px, red var(--l)) 80px 20px, conic-gradient(at 40px 60px, #fff var(--l)) 40px 60px, conic-gradient(at 20px 80px, red var(--l)), repeating-linear-gradient(45deg, red 0 1.41px, transparent 0 2.83px);background-size: 100px 100px;background-blend-mode: normal, normal, color, difference
background: conic-gradient(transparent 25%, #a17bb6 0% 50%, transparent 0% 75%, #fff 0%) 0/ 4em 4em, repeating-conic-gradient(#a17bb6 0% 25%, #fff 0% 50%) 0/ 0.5em 0.5em
--l: #0a0432 calc(50% - 4.24px), #fff 0 calc(50% + 4.24px), #0a0432 0;background: linear-gradient(90deg, #fe0478 25%, #afec32 0% 50%, #f35932 0% 75%, #0affd3 0%) 0/ 384px, repeating-conic-gradient(#fff 0% 25%, #0a0432 0% 50%) 0/ 12px 12px, linear-gradient(45deg, var(--l)) 0/ 96px 72px, linear-gradient(-45deg, var(--l)) 6px/ 96px 72px;background-blend-mode: darken, darken, lighten
--l: transparent 49%, #c1986b 50%, transparent 51%;--s: / 5.142em 6.128em;background: linear-gradient(50deg, var(--l)) 0 var(--s), linear-gradient(-50deg, var(--l)) 0 var(--s), repeating-conic-gradient(from 40deg, #2f4d7f 0% 100deg, transparent 0% 50%) 2.571em var(--s), conic-gradient(#26a9e1 50%, #b87b83 0% 75%, #d4b57e 0%) 2.571em/ 10.284em 12.256em
--l: transparent 49%, #fff 50%, transparent 51%;background: repeating-conic-gradient(from 40deg, #c71585 0% 100deg, #8a2be2 0% 50%) 0/ 7.714em 9.192em, repeating-conic-gradient(from 40deg, #b3b3b3 0% 100deg, #4d4d4d 0% 50%) 3.857em/ 7.714em 9.192em, linear-gradient(50deg, var(--l)) 0/ 3.857em 4.596em, linear-gradient(-50deg, var(--l)) 0/ 3.857em 4.596em;background-blend-mode: color, difference, normal
--l: transparent 49%, #fff 50%, transparent 51%;--p: 0% 126.86deg, transparent 0% 50%;background: linear-gradient(63.43deg, var(--l)) 0 0/ 3em 6em, linear-gradient(-63.43deg, var(--l)) 0 0/ 3em 6em, repeating-conic-gradient(from 26.57deg, #1b1c4a var(--p)) 0 0/ 3em 12em, repeating-conic-gradient(from 26.57deg, #147fa3 var(--p)) 0 6em/ 3em 12em, repeating-conic-gradient(#fcb543 0% 25%, #f3753b 0% 50%) 0 0/ 6em 12em
--a: #000 calc(50% - 5.66px), #7d4caf 0 calc(50% + 5.66px), #000 0;--b: #9f7cc7 0% 25%, #000 0%;background: conic-gradient(at 8px 8px, #000 75%, #cfa7ff 0%) 28px 60px/ 4em 4em, linear-gradient(45deg, var(--a)) 0 0/ 4em 4em, linear-gradient(-45deg, var(--a)) 0 0/ 4em 4em, repeating-conic-gradient(var(--b), #601286 0% 50%) 4px 4px/ 1em 1em, conic-gradient(from 45deg at calc(50% + 8px), var(--b)) 0 0/ 4em 4em, conic-gradient(from 225deg at calc(50% - 8px), var(--b)) 0 0/ 4em 4em;background-blend-mode: lighten
--b: #0c0922 0% 25%, #fff 0%;background: conic-gradient(#f88f22 25%, #83a1f3 0% 50%, #35627f 0% 75%, #f5d07d 0%) 0 3em/ 12em 12em, repeating-conic-gradient(var(--b) 50%) 12px 4px/ 1em 1em, conic-gradient(from 45deg, var(--b)) 0 0/ 6em 6em, conic-gradient(from 225deg, var(--b)) 0 0/ 6em 6em;background-blend-mode: darken
--l: transparent 49%, #000 50%, transparent 51%;--s: 0/ 3.441em 4.915em;background: linear-gradient(55deg, var(--l)) 0 var(--s), linear-gradient(-55deg, var(--l)) 0 var(--s), repeating-conic-gradient(from 35deg, #f2eed5 0% 110deg, transparent 0% 50%) 1.7205em var(--s), linear-gradient(#e27b38 20%, #48a6a8 0% 40%, #e8b838 0% 60%, #de3c37 0% 80%, #8b9d47 0%) 1.7205em -2.4575em/ 1% 24.575em
--l: purple 0 2px, transparent 0 4px;background: repeating-conic-gradient(from 45deg,transparent 0% 25%, #eee 0% 50%) 1px 1px/ 40px 40px, repeating-linear-gradient(var(--l)), repeating-linear-gradient(90deg, var(--l))
--l: 65%, #ccad77 25%, transparent 0% 50%, #000 0% 75%, transparent 0%;background: conic-gradient(at 50% var(--l)), conic-gradient(at 35% var(--l)), repeating-conic-gradient(at 35% 65%, transparent 0% 25%, #cbaa03 0% 50%), repeating-linear-gradient(45deg, transparent 0 2.83px, #cbaa03 0 5.66px);background-size: 6em 6em;background-blend-mode: lighten, darken, difference
--l: 25%, transparent 0%;background: conic-gradient(at 6em 2em, #fff var(--l)) 2em 2em/ 8em 8em, conic-gradient(at 2em 6em, #7cc5fc var(--l)) 0 4em/ 8em 8em, conic-gradient(#1b3160 var(--l)) 0 0/ 4em 4em, repeating-conic-gradient(#7cc5fc 0% 25%, #1b3160 0% 50%) 0 0/ 4em 4em, repeating-linear-gradient(45deg, #fff 0 2.83px, #000 0 5.66px);background-blend-mode: lighten, darken, normal