snapshot of solar system I am working on a little project where I want to simulate the solar system to teach myself working with python and OOP.

I want to calculate the orbits "real", from tangential velocities and gravitational accelerations. For this, in order to not only get circular orbits, but the real, eccentric orbits, I need kind of a snapshot of the solar system with positions and tangential velocities at those positions of the planets (and their moons, but I highly doubt that exists). 

EDIT: I think something like the velocities at the Apoapsis should be enough to derive a reasonably right orbit from it, right?

I don't even know if something like that exists, or where to get it from. Does anybody happen to know something of this?
You can get a position and velocity snapshot easily using the Python package Skyfield. It downloads a JPL Development Ephemeris and then interpolates the positions for whatever time you choose for your snapshot.

You can also use JPL Horizons to produce one or thousands of positions of solar system bodies.

This answer describes how to set up Horizons to save positions to your computer, and includes a script that can read the format of the saved tables. It also happens to be a simulator that does what you are talking about - statrs with a given position and propagates the orbits.