mgsx_mod

Good for SFW
Imagevenue - Reliable and relatively fast.

Good for NSFW
Squidge - Up to 256 MB per image for members, allows all drawn kinks, except for loli/shotacon. Best used for guro, bestiality art.
Postimages - Allows all art legal in the US.

Lolicon/Shotacon specific hosts
Baraag - Made specifically to host loli/shota art. They host realistic loli/shotacon often. Make a private post and get the image link from there.
Aethy - Made specifically to host loli/shota art. Make a private post and get the image link from there.
Cutefunny.art - An invite only mega/dropbox cloud made specifically for hosting loli/shota art. Contact the admin of the site for space.

Reliable, but...
Catbox - the TOS forbids uploading sexualized depictions of minors, bestiality and sexual violence, but due to the sheer amount of lolicon, fictional bestiality artwork and rape artwork I have seen uploaded to catbox with no repercussion, I am led to believe this is about RPF. If your artwork is especially realistic, especially if your lolicon is realistic, keep it to Baraag. The only downside to this is that catbox is blacklisted in many countries, and confuses users.

Paid services
Buying your own server space - The best option. Use a US host. A great resource.
Cutefunny.art - An invite only mega/dropbox cloud made specifically for hosting loli/shota art. for 600JPY a month, you get 30gb of loli/shotacon hosting.

Services to avoid
Imgur
Also, don't use Imgur to host image libraries you link to from elsewhere, content for your website, advertising, avatars, or anything else that turns us into your content delivery network. (x)
Discord
Discord image links now have a built in expire date for hotlinked/embedded images. Do not use discord to host your fanart.
ImgBB
Your Contributions are not obscene, lewd, lascivious, filthy, violent, harassing, libelous, slanderous, or otherwise objectionable (as determined by us).(x)