In the US, I’m not sure if there ever was a “compulsory education age”. But in the late 19th/early 20th centuries children were often used in many fields, albeit mostly blue collar. They would work on farms or in factories and were expected to work long hours usually. Boys and Girls both could work in some of the sweatshops of the day if they had the skills.

Throwing news papers?

In my area kids worked the farms in lieu of school. My grandmothers family attended to 8th grade I believe, the boys anyway. They were literally put in harness to plow as young as 8 years old and had to do chores before school and plow afterwards.

Working at a casino. Housekeeping. Manual labor.

So many of them. At that time, skills were passed on in an apprenticeship model. Kids learned on the job rather than receiving more formal education. Making a comprehensive list of jobs for a 14-year-old a hundred years ago would be impossible, but here’s some examples I’ve read about:

junior teacher (yes, kids would leave school as students, and then return to teach a few weeks later)
apprentice baker
shoemaker’s apprentice
apprentice blacksmith
delivery boy
apprentice miller
servant
chef’s assistant
carpenter’s apprentice
draper’s apprentice
in more urban settings: bellhop, clerk, mechanic
more exploitative work with little chance of moving up: mining, factories, farm work
limited options for girls: service (maids, childcare), teaching, secretarial work

I’m in the US. I started working in retail at age 14.

I would assume in the early 1900’s they worked on farms, and worked as an apprentice for many skills like iron working, and actually the jelly above me already hit on many of the jobs that came to my mind.

Everyone in my family did part-time jobs as kids, but I will assume the question is about full-time work.

A couple of examples:

Textiles – “Between 1880 and 1910, manufacturers reported that about one-quarter of their workforce was under sixteen years of age”

Mining ”“Shorpy Higginbotham, a ‘greaser’ on the tipple at Bessie Mine, of the Sloss-Sheffield Steel and Iron Co. in Alabama. Said he was 14 years old, but it is doubtful.”

In my area, 14 and 15 year olds will do things like buss tables (meaning to take the dirty plates off tables in restaurants, and set up the clean tables with silverware and napkins for the next diner). They may wash dishes. They may work in a coffee shop. Hours are limited by law during the school year but they can work longer hours on summer break.

When my dad (b. 1913) was 14 he dropped out of sixth grade and went to work on a house moving team. They used a team of six horses and rolled the houses down the street on wooden logs.