A fantastic collection of various deep space objects, imaged in HaLRGB by Jim Misti. Working with just the L (luminance) frames, before delving into HaLRGB combining, is great way to learn the ropes.
Results are free to publish, as long as they are credited "Image acquisition by Jim Misti".
Even the way StarTools displays and scales images, has been created specifically for astrophotography.
StarTools' Detail-aware Wavelet Sharpening allows you to bring out faint structural detail in your images.
You can convert everything you see to a format you find convenient. Give it a try!