Strapon
A strapon opens up a lot of options that a regular dildo just doesn't. You can go strapless, where one end sits inside the vagina and holds itself in place during use, or pick a harness with a swappable dildo if you want more control over size and shape. There's also the hollow version that fits over a penis, which works well for couples dealing with erectile difficulties. And if you want simultaneous penetration, double-penetration designs handle that too. Most people start with a harness kit because the fit is more secure, but honestly the strapless styles have improved a lot in recent years and are worth a look if you prefer something more minimal.