Watch list of Tweets with unknown model
There are several steps:

Setup a system that collects tweets from certain accounts.
Preprocess the tweets to create tokens that similar to the tokens in the pretrained model (e.g., lowercase and/or stem).
Create two sets of watch list tokens and tweet tokens. Take the intersection of the two sets.

There are two options for tokens that in tweets but not in pretrained model:

Ignore them.
Explicitly model them as &quot;UNK&quot; / unknown