I tried like following.
MyList.RemoveAll(t => t.Name == "ABS");
MyList.RemoveAll(t => t.Name == "XYZ");
MyList.RemoveAll(t => t.Name == "APO");
Instead how can I do something like:
MyList.RemoveAll(t => t.Name == "ABS" || t => t.Name == "XYZ" ||t => t.Name == "APO");

You only need one lambda expression - the || goes within that:
MyList.RemoveAll(t => t.Name == "ABS" || t.Name == "XYZ" || t.Name == "APO");
In other words, "Given a t, I want to remove the element if t.Name is ABS, or if t.Name is XYZ, or if t.Name is APO."
There's only one "given a t" in there, which is what the t => part means, effectively.
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