Postgres names are surprisingly flexible

As long as the Postgres server uses UTF-8 as its encoding, you can create a table with emojis as the name.

CREATE TABLE 💩😀🤔 (
  id BIGINT PRIMARY KEY GENERATED ALWAYS AS IDENTITY,
  name TEXT NOT NULL
);
 
INSERT INTO 💩😀🤔 (name) VALUES ('poop');
-- INSERT 0 1
 
SELECT * FROM 💩😀🤔;
/*
 id | name 
----+------
  1 | poop
(1 row)
*/

Notice that you don't need to quote the emoji name. Given that there's no case-folding with emojis, emojis are superior to uppercase letters in table names in this one respect.

There are surprisingly few restrictions to what you can name your tables:

• Quoted identifiers can contain any character, including spaces and punctuation.
• The length of an identifier is restricted to NAMEDATALEN - 1 bytes. NAMEDATALEN is 63 by default, but can be set at compile time.

All of these are valid identifiers, which means you can use them as table names:

• " "
• "This is a valid identifier!!"
• 表名
• "..."
• "SELECT"

Identifiers don't need to be quoted if they "begin with a letter (a-z, but also letters with diacritical marks and non-Latin letters) or an underscore (_)."

All the above rules apply to all identifiers, including column names, index names, and constraint names:

ALTER TABLE 💩😀🤔
  ADD CONSTRAINT "🚫 empty names! 😤" CHECK (length(name) > 0);
-- This adds a constraint named "🚫 empty names! 😤" to the 💩😀🤔 table.

Please don't do this. However if you choose to do this, please tell me all about it.

See https://www.postgresql.org/docs/current/sql-syntax-lexical.html for more details.