Actually sex aides that date back to prehistoric times have been discovered that are covered in a patina of female sex fluids so they most certainly were around in Biblical times! My feeling is it is not mentioned in the Bible because it wasn't considered a bad or good thing....it simply was so obsequious that it wasn't deemed worth of expounding on.

Taking what I, myself, would reason: If the toys are not taking your focus off of your partner and cheating him/her out of time or emotional connection with you then how could they be harmful. Studies, and I mean real ones not done by the right wing fringies who want to control everything sexual, show that even frequent use doesn't cause stretching of the vaginal barrel or de-sensitization of the clitoral nerves.

Masturbation for males was mentioned because of the erroneous belief that men had a limited amount of seminal fluid (humors) and would in effect run out if they masturbated too often. We now know that proper prostate health depends on the prostate being emptied fully and often so in effect denying a man the right to rub can actually cause him harm...and it really does no harm so long as he isn't cheating his partner of intimacy or time.

Personally, my God isn't a sex police type God. I am responsible for my health as best as I can manage it and I am also responsible to look and be sure I am not developing bad habits....and if I do I seriously doubt God will punish me because the effects of my actions will have natural consequences.

I was raised Catholic and I was never taught that sex toys were bad as long as they brought joy to a married couple and added to the couple's pleasure. So I think I'd have problems with a group who espouse that philosophy.
Trust your relationship with God and let other humans have their views! You are not responsible for what other's believe God wants...listen and let Him tell you.