nullroute's list is right and I'd add the practical shape of what people actually do at thirty, because "all different" is not a plan anyone sustains past month four.
What tends to survive contact with reality is three or four clusters rather than thirty singletons. Say ten sites at ExtraVM, eight at Virtualine, seven at Servury, five somewhere else — different providers, different ranges, different billing, and crucially different dates, because you build the clusters over months rather than in one weekend.
Within a cluster you're not pretending they're unrelated. You're pretending they're an unremarkable small hosting account, which is what they are. Thirty separate accounts at thirty providers is anomalous in a way that ten normal-looking accounts is not, and the anomaly is the thing you're trying to avoid.
On providers specifically: ExtraVM from $3.50 with no documents on crypto payment is the workhorse for this and multiple regions helps. Virtualine is the price-per-performance pick at about €4 and takes Monero, with the old kycnot.me note about the billing panel being a nulled WHMCS copy — I keep that on the record but it hasn't caused anyone I know an operational problem. Njalla at €15 is triple the money and you'd only put the sites that matter there.
The variable I'd actually spend the admin effort on is the stack fingerprint, not the provider count. Three different web servers across the clusters costs you nothing but attention and breaks a correlation that IP diversity doesn't touch.
I have not run a network above about twenty properties, so treat the cluster sizes as a shape rather than a rule.