Supercool/awesome/random apps

Just as the title say do you guys have any supercool/awesome/any types of apps that are useful, you use? Like I have a Chinese app that like pintrest or Instagram, you can download it : 小红书 (Xiaohongshu) . I love using this.! It's so much nice that Instagram too!. Anyway so, I just wonder that there might be so many apps, that I don't know about like apps that can help with anything or research anything. So I am just asking if you guys have apps that are unique and not so common like secret app that super helpful! Do share me some..!(づ￣ ³￣)づ and thank you for seeing this question! ヾ(☆▽☆)