What's the best wish list tool?

Very useful, easy set up, low cost

Wishfinity allows consumers to maintain a centralized wishlist of all the things they want regardless of a particular retailer, brand, or seller.

One list to manage with privacy settings and sharable functions per entry. Use it like a link tree if you have multiple lists elsewhere (Amazon, Coda, individual retailers, etc.) For influencers use your referral or short-links to track the shares instead of upvotes.

It's a more general app but still can be used for wishlist

It's a universal wishlist app for shoppers! It allows people to save products from several online stores and get sale alerts! If someone want to create a shopping wish list, I recommend WISHUPON 💫

You can create Ideas and Publish them, Add your friends, Create a Public and private wish list.

Create Wish Lists and share them with Friends

They've got a user-facing voting system that allows users to submit their product ideas, other users to up/downvote, and moderators to update on status. I haven't used it in a while (used it at my previous workplace) but it sounds like it has what you're looking for.

Gift Hero is easy to use, intuitive and allows you to add anything from anywhere.

It's simple to use and quick to set up.

DreamList is private, family-friendly, and truly universal. It is not tied to a retailer, so you can add the lowest price items from anywhere (and link your other wish lists and registries). It lets you manage wish lists together with your spouse or team for Birthdays, Christmas and other Holidays, Baby Showers for little ones, etc. (very very handy for parents, charity gift drives, and disaster recovery teams). More importantly, you can add large items and dreams you are saving towards such as a big trip to Disney, or 529 plans, so on special occasions family can contribute small amounts to help little ones get there sooner.