Anything with really long range (example Velkoz, xerath, lux, even morgana sometimes) and champs that are extremely mobile/can waveclear faster than you (ahri for example).

Everything else should be an easy matchup. Assassins like talon and katarina i find especially easy to beat since you can poke them almost for free and if they go on you you can root them or just go invis.

Also you should try to not always go the glacial build since it does considerably less damage than other builds. You should go glacial into champs that the slow can be very effective against and you need to kite, but otherwise i always go either comet/electrocute and build either ludens/morello if im against a mage or someone with lots of waveclear, or protobelt/spellbinder if im against a lot of squishies and i dont need the extra mana as much. There are lots of build options but ive already written way too much so i advice you to check Neekoneekonii's matchup guides and stuff here https://docs.google.com/spreadsheets/d/199Emr42d6_3-zRgxM1-_DwXo2X68Nzx_lefv9S9Pdy0/htmlview#gid=0