This post considers places where the Dative of Agent invades what would normally be constructions suitable to the Ablative of Agent.
With Passive Perfect Participles
With passive verbs, the Dative of Agent is most common with perfect passive participles, especially when these are virtually adjectival.
- It has been deliberated and established by me: mihi dēlīberātum et cōnstitūtum est.
- This has been provided for by you: tibi haec prōvīsa est.
- The lights have made me dizzy: lūcibus cālīgātus sum.
Note that, with the final expression, lūcibus may be either Dative or an Ablative of Instrument (but not an Ablative of Agent, since there is no ā/ab). In this case, assume it’s an Ablative of Instrument, which is altogether more common, especially with something inanimate like ‘lights.’
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With Passive Verb
The Dative of Agent is not unheard of with standard passive verbs, especially with the poets.
- He is not seen by anyone: nōn cernitur ūllī.
- He was favored by the nymph: Nymphō fovēbātur.
With Videor
The construction ‘it seems to x‘ is expressed with videor, vidērī, visus + Dative of Agent.
- He seemed to me a horse with wings: mihi equis cum ālīs vidēbātur.
- It seemed otherwise to the gods: dīs aliter vīsum est.
- It seems to me that you are a slob: sordidus mihi vidēris.
With Probō
According to AG, probāre takes a Dative of Reference, but it’s so regularly attached that it seems like a Dative of Agent. I’m not sure I buy this, but here’s what they mean:
- This view was approved by both him and me: haec sententia et illī et mihi probābātur.
- This plan was not approved by the majority: hōc cōnsilium plēris nōn probābātur.
The Essential AG: 375
Latin for Addicts 
Nice explanation. I agree about probo. On the other hand, I’d like to ask about your second example under PPP’s. “This has been provided for you: tibi haec prōvīsa est.”
If we’re talking dative of agent, wouldn’t that read, “This has been provided by you”? The current translation seems to me (mihi videtur) to be a dative of advantage/reference.
I think my revision (see above) should make things clearer.
The sentence that AG presents: “mihi rēs prōvīsa est.” -Cicero, Contra Verrem, iv. 91 ‘The matter has been provided for by me.’ This still sounds awkward, rendered in English.