If your bottle top diameter is 1.75 inches/4.5cm https://www.amazon.com/Froz-Ice-Ball-Maker-Food-Grade/dp/B00H8W54EK/ref=pd_aw_lpo_79_bs_img_1?_encoding=UTF8&psc=1&refRID=H9WTD2Q76ZVVYSR82FF5
If it's 2.5 inches/6.35cm
https://www.amazon.com/Tovolo-Leak-Free-Sphere-Molds-Silicone/dp/B007ACTN54
Holy crap I cannot recommend this water bottle enough! It's this 32 oz Embrava Sports Water Bottle ($22) that I got off Amazon! It definitely leak proof, doesn't add any weird taste to the water, it can hold a lot of water without being ginormous, it has really fast water flow (to the point where you kinda have to get used to it when you first get it), it's overall amazing! 10/10 highly recommend!
I love these because of the design. And the great price.
Hiwill Stainless Steel Insulated Water Bottle 2 Lids, Cold 24 Hours Hot 12 Hours, Double Wall Vacuum Thermos Flask, Travel Sports Leak Proof Metal Bottle with Straw, BPA Free (Tropical Seas, 37 OZ). https://www.amazon.com/dp/B07HF42KSR/ref=cm_sw_r_cp_apa_i_KM4SCb30XPKRY
For anyone wondering the pitcher is a Zero Water 23 Cup Pitcher. I prefer it over Brita because this filter removes all total dissolved solids while Brita only removes 25% or so.
I've heard this is unsafe as the plastic starts to break down and leak into bottle.
Get yourself one of these https://www.amazon.com/gp/product/B01BEX7LR6/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1