https://www.iosicongallery.com/ iOS App Icons
https://pictogram2.com/ 人類活動標誌 免費商用無需 Attribute 請注意：有關於無障礙的標誌是有規定的，若想使用有關無障礙的相關意思的標誌，請從國家政府機關下載。
https://iconstore.co/ You can use the icons in personal and commercial projects You can modify the icons No attribution required (although it's appreciated!)
https://smarticons.co/license as long as you’re not using more than 50 icons per project.
https://iconduck.com/licenses/mit 最好只選擇 MIT