special
legitimate, reasonable
unreasonable
formal, official
polite
direct
I could not deny a direct request like that.

simple
odd, strange, unusual
initial, original
I made my initial request for material in February.

final, last
Her last request before she died was that she be buried at sea.

numerous, repeated
urgent
explicit, particular, specific
email, written
I got a couple of email requests for it.

interview
He has refused all interview requests.

budget, funding (both esp. AmE)
the State Department budget request

extradition
an extradition request by the US

make, put in, send, submit
I've put in a request for a room with a view of the sea.

get, have, receive
We have had repeated requests for a pedestrian crossing near the school.

consider, review
The judge will now consider this request from the plaintiffs.

accept, agree to, grant
accommodate, comply with, fulfil/fulfill (esp. AmE), honour/honor, meet
His request was always met with the same answer.

approve
The Commission approved a request for $700 000 in tax refunds.

answer, respond to
deal with, handle
ignore
decline, deny, refuse, reject, turn down
repeat

at sb's request
The book was withdrawn at the author's request.
The play was written by Agatha Christie at the request of Queen Mary.

by request
The writer's name was withheld by request (= because the writer had asked for this to be done).

on request, upon request
Additional copies will be made available on request.

request for
The helpline was inundated with requests for information on the crash.

available on request, available upon request
A detailed list of our publications is available on request.

by popular request (esp. BrE) (usually by popular demand)
The movie is being shown again by popular request.

a number of requests

explicitly, specifically
formally, officially
politely
simply
She had left him a message, simply requesting that he call her back.

reasonably (law, esp. BrE)
Auditors will be required to provide any information reasonably requested by the bank.

urgently
repeatedly

from
We have requested some information from the company.

Request is used with these nouns as the subject:
email, petition

Request is used with these nouns as the object:
anonymity, assistance, asylum, audience, authorization, autopsy, balance, catalogue, clarification, clearance, copy, exemption, extension, extradition, funding, hearing, help, indulgence, information, interview, leave, loan, meeting, permission, permit, postponement, presence, recognition, refund, reinforcement, report, return