D3 Scale Chromatic — perceptually uniform gradients (Viridis, Magma, Plasma, Turbo, CubeHelix, etc.)

cpt-city — 7,200+ scientific color gradients from cartography, data viz, and art. Bulk SVG import.

Resource Boy — 4,600+ Photoshop .grd gradients across 23 themed packs (duotone, chrome, holographic, retro, etc.)

Gradient Hunt — 2000+ community-curated CSS gradients (linear & radial) via PHP API

Eggradients — 400+ named gradients extracted from SVG definitions on CDN

MyColor.space — gradients generated from seed colors using color space algorithms

CSS Gradient swatches from cssgradient.io

Grabient — 99 cosine gradient palettes with mathematically smooth color interpolation (Inigo Quilez technique)

ColorBrewer — scientifically designed color schemes for cartography and data visualization (diverging, sequential, qualitative)

uiGradients — ~350 curated linear gradients from GitHub JSON

WebGradients — 180 linear gradients with angles and stop positions

CoolHue — 60 two-color gradient pairs

Hypercolor — 80+ curated Tailwind CSS gradients with named palettes

Gradient Magic — 1100+ CSS gradients including complex patterns, stripes, grids

Hypercolor Flags — 60+ country flag gradients as CSS

Color-theory generated gradients — 2000 algorithmic gradients using complementary, triadic, analogous harmonies