There are many unfortunates who got a chance to play exactly one Test (or ODI or T20I). Some of them did well enough to deserve more chances but somehow this never happened. We look at the batsmen who made the most of their chances in limited Test opportunities, and then in ODIs and T20Is.
Scoring at least one fifty in their only Test:

Of these, only Redmond scored a hundred and a fifty, and Ganteaume scored a hundred. SC Cook played his only Test so far in 2016 and should get off this list soon. Ronchi is the only one to score over 100 runs without a century, while three others scored over 90.
There are various reasons why they did not play again. Eyesight issues were the main reason for Rodney Redmond not playing again. His son Aaron Redmond played 8 Tests in recent years with a top score of 83.
Zulqarnain Haider stopped playing for Pakistan under peculiar circumstances. Cook and (perhaps) Ronchi should play again. India’s sole representative the Yuvraj of Patiala (also known as Yadavindra Singh) dropped out of cricket to concentrate on politics, though he might well have captained India in the 1936 tour of England where he would certainly done better than Vizzy. His son Amarinder Singh is still active in the politics of Punjab state.
Now we look at
Scoring at least 50 runs in their only Test:

This includes a few others who made 50 or more runs without a fifty. The highest total among these is JK Moss with 60. There is also Humayun Farhat, who did score 54 runs in his only Test but also became the only wicket keeper who did not make a single dismissal in his career. (There are some other keepers who did not make any dismissal on their debut).
Scoring at least fifty in their only Test innings:

Ganteaume and Stollmeyer lead here. Albie Morkel probably deserved to play a few more Tests, but is now unlikely to get another chance. And McGirr played his only innings in his 2nd and last Test, as he did not get to bat on his debut. Law is the only one in these tables to remain unbeaten in his short Test career. His fellow Australian debutant RT Ponting went on to bigger things.
Now for ODI matches:
30 or more runs in their only ODI:

Barnett and Woodcock are the only ones to score fifties, though there are several others close behind. Some of them were moderately successful in Tests, such as AV Mankad.
30 or more runs in their only ODI innings:
We get exactly the same list as above.
Now for T20Is:
20 or more runs in only T20I:

India’s lesser-known S Badrinath has the highest score here. Dinesh Mongia’s only T20I was India’s first. Some prominent Test and ODI players such as Dravid, Ganga, Gillespie and North find a place here, along with the hapless Reifer who was once asked by journalists “Are you smoking something which sounds like your name?”. This was at that the time he captained a West Indies C Team which gave Bangladesh its first two Test victories away from home.
20 or more runs in only T20I innings:
We get exactly the same result.
To be continued with bowling, fielding and all-round performance in their only match or innings.