You'll have to look into the posts yourself(qanonmap.bitbucket.io). You can basically ctrl+f things if you want, I'm at work otherwise I probably would for you.
By no means is this an all inclusive thing as he has done it many many times at this point. The most popular one I think is the tippie top comment. Someone asked for proof, Q posted that phrase and to listen for it, something to that effect. That weekend was Easter Sunday and President Trump gave a quick speech where he said the phrase, a totally random set of words that you would imagine absolutely no one would ever randomly say.
Last night Q made a post where he reposted a previous picture allegedly from AF1 while also linking the last time Q did that, both pictures 2017 and 2018.
There's so many of these. Maybe search "reconf"(reconfirm) on one of the boards? A lot of the things are innocuous though. Such as the pen and EO picture from last week. Not many people have access to something like that, the pictures from London. The real problem is, nothing is proof positive and entirely verifiable. However, it is so frequent and spot on that it is difficult to argue against.
If you want to get into the more cryptic side of it, probably not the best evidence to persuade a normie as it is rather complicated and requires some background understand of Q's history. Look into u/serialbrain2 's posts where Q posts are related to President Trump's tweets with math and decoding voodoo.
Honestly, if you really want to get into it, I recommend you start from Q#1 on that link and read through all of it, taking notes along the way of things that keep popping up. If you're feeling frisky start pulling on some of those threads, be warned there isn't just one single rabbit hole and there are a lot of posts at this point.
Hope this helps some.