The honest way to pick: dedicated single-purpose tools vs all-in-one suites, and when each wins.
Free CSS generators broadly split into two categories, and the "best" one depends on which you actually need:
If you have one very specific, recurring need — you're building color palettes constantly, or your team lives inside gradient design — a tool built around exactly that one workflow can be worth the extra bookmark. The tradeoff is context-switching: a project that needs a gradient today and a box-shadow tomorrow means juggling multiple different sites, each with its own UI conventions to relearn.
This site (css.ignlab.net) is deliberately the second kind: 14 generators — glassmorphism, gradients, shadows, animations, layouts, OKLCH colors, bento grids, scroll animations, border-radius, fluid typography, grid areas, filters, easing curves, and buttons — behind one consistent UI, all free, no sign-up, 100% client-side. The honest tradeoff versus a dedicated single-effect tool: you get one interface to learn instead of many, at the cost of not being quite as deep on any single effect as a tool built around nothing else. For most day-to-day front-end work — where the effect you need changes project to project — that tradeoff favors the all-in-one approach.
It depends on how varied your CSS needs are. If you need many different effect types across projects, one all-in-one suite avoids relearning a new UI for each effect. If you have one deep, recurring, specific need, a dedicated tool built around exactly that workflow can be worth it.
Yes, as long as the tool runs client-side (check that it doesn't require uploading your design or code to a server) and the output is plain CSS you can read and understand before shipping it — you're not adding a runtime dependency, just copying generated CSS text.
Some do, some don't — it varies by tool. Every generator on this site outputs both raw CSS and the equivalent Tailwind utility classes.