One with Emma Frost, and the other being when someone mimicked his powers so they were obligated to experience The Void and couldn't handle it.
Ahh. Granted the Void and Death Seed Sentry are no longer one and the same, thus I suppose his feats are inadmissible. I imagine soon Rick will be flirting with Sentry's telepathy levels, since he seems to be more powerful in other regards.
Assuming Ulton isn't so regularly affected by it, 2/3rds haven't exhibited sufficient telepathic resistance to suggest they could withstand an offense on that front(from someone as powerful as Thanos, and otherwise Ultron would be overpowered).
I'm not sure Thanos could enter DSS mind.
Edit** albeit it only due to hearsay reports of the Death Seed being immune to telepathy.