Across
I am angry; I may become fanciful (9)
In beds, one’s flipping long-suffering (5)
I haven't cracked this one yet — but Fifteensquared have:
I="one" is in COTS="beds", reversed/"flipping"
Quaint insolence upsetting but trivial (15)
Believe king should be deposed, being weak (4)
I haven't cracked this one yet — but Fifteensquared have:
definition: 'thin' can mean 'weak' in e.g. a 'thin argument' THIN-[K]="Believe" with K ("king", chess abbreviation) removed
Tree flattened, by psychic power? A fib, right? (8)
A magazine to deliver, one filled with party spirit (5,4)
Tried the patience of top managers when speaking (5)
From the start, no ancient historian underestimated minor prophet (5)
I haven't cracked this one yet — but Fifteensquared have:
definition: a prophet in the Bible starting letters of N-[o] A-[ncient] H-[istorian] U-[nderestimated] M-[inor]
Hurried to finish the ironing? (7,2)
Gets wrong impression of motorway cuts (8)
A service returns from a distance (4)
In funny cartoon, wag omits enough space (4,2,5,1,3)
Had extra sleep, to build up supplies (3,2)
Prohibited area, as hygienic kitchen should be? (2-3,4)
I haven't cracked this one yet — but Fifteensquared have:
a hygienic kitchen would have no flies (the insects)
Down
Fool, standing up to African dictator (5)
I haven't cracked this one yet — but Fifteensquared have:
reversal upwards (standing up) of TO (from surface) + IDI (Idi Amin, African dictator)
From which you may come away with a lot (7)
North Europeans won’t open pubs (4)
I haven't cracked this one yet — but Fifteensquared have:
[F]-INNS="North Europeans" without the opening letter
Top copy, with illiterate’s signature (4)
I haven't cracked this one yet — but Fifteensquared have:
APE="copy" + X=symbol that could be used as a signature by the illiterate
QI signature for solvers (10)
Saturday better for smart clothes, but … ? (6,4)
Old organ drowning one actor (7)
I haven't cracked this one yet — but Fifteensquared have:
definition: Laurence OLIVIER the actor O (Old); plus LIVER="organ" around I="one"
American statesman has some guts, touring drama school (9)
Barmen itch excitedly to pour this? (10)
In contrast, firm with a thousand working across Olympic city (10)
I haven't cracked this one yet — but Fifteensquared have:
CO (Company, "firm"); plus M (thousand in Roman numerals) + ON="working" around PARIS="Olympic city"
Burn ample rubbish, somewhat shady (9)
I haven't cracked this one yet — but Fifteensquared have:
anagram/"rubbish" of (Burn ample)*
Man’s right-wing background (7)
In practice, certainly about to perform (2,5)
Bind over again, reducing sureties (5)
Cockney burglar’s land grant? (4)
I haven't cracked this one yet — but Fifteensquared have:
someone with a Cockney accent might pronounce the word 'thief' ("burglar") like FIEF
Like something scrambled, say, extremely gently (4)
Type letters or click words in the clue