How to eliminate indoor insects with organic techniques?

I'm not sure about the lizards because I live too far north for them. Borax is useful for ants and fleas. Mix 1/2 cup sugar, 1 1/2 tablespoons borax and 1/5 cups warm water to dissolve the sugar and borax. Soak cotton balls in it and set them out where you see ants. The ants come to eat the sugar and the borax kills them.

Diatomaceous earth is also a great natural way to kill bugs. If it's really bad, I sprinkle it around my home on the outside. Just make sure it won't rain for a few days.

Peppermint essential oil also repels bugs. Put a few drops on cotton balls and set them where you see the bugs.

I hope someone else can answer about the lizards. Good luck!

Borax mixed with powered sugar is great for getting rid of ants. However, if you have even lizards invading the house, I am guessing that the root of the problem may be missing weather sealing along the base of your doors. Here are some tips to help with that https://www.hometalk.com/diy/repair/windows/boost-your-home-s-efficiency-with-weather-stripping-1900631

Boost Your Home's Efficiency With Weather Stripping

(1) If you have a basement or a crawl space, have spray foam insulation sprayed into the sill or the rim joist cavities to seal all cracks and crevices. This will also help with your heating/cooling bill. Insects can squeeze into your basement through the tiniest of openings and foam insulation will block them, as well as rodents (and lizards!), from entering. (2) If you have a poured or block concrete foundation crawl space or basement, check everywhere for cracks and openings inside and outside and seal with foam sealant or hydraulic cement (small to medium size cracks) or polyurethane concrete injection for larger cracks. (3) Make sure your grading outside is up to par and draining water away from your foundation, and clean up brush, leaves, weeds, and trim shrubs that are growing too close to the foundation. (4) Sprinkle ant granules around the outside foundation of your home - they work great. (5) Install and use a basement dehumidifier. (5) Some suggestions for green remedies - also do a search online, tons of recommendations for using natural oils, pepperment oil, etc. to get rid of bugs. https://www.fightbugs.com/keep-spiders-out-of-the-basement/ (6) Have a pro come out once a year to spray inside and outside if you have a recurring problem. Well worth the cost. (7) If you have windows, check for air infiltration around the window. If you feel air leaking, that means insects can also squeeze in. If you open the windows for ventilation in the basement, be sure you have secure screens and apply proper weather stripping around the window so it seals tightly when closed. If you don't open your windows, seal with foam. If you have glass block windows, check for cracks and tiny openings in the concrete around the blocks and repair as necessary.

I had spray foam insulation installed in my basement sill in 2009 (I live in SE Wisconsin and we get sub-zero temperatures in the winter) and it made a tremendous basement in cutting down on spiders and other creepy crawlies and helping both my heating and AC bills during winter and summer. It was well worth the cost in the improving the comfort level in my unfinished basement. It also cut WAY down on the humidity in the basement. My area of Wisconsin gets hot and very humid during the summer, and is bitter cold and very damp during the winter.

Hope this helps.

Try diatomaceous earth for everything except lizards. It will work inside and out as long as it doesn't wash away, even if it gets wet. It won't harm pets or children, even if ingested. I've seen it at Lowe's and Tractor Supply.

Try checking for any cracks where light can pass. If it is, seal it up. You can use caulk.

Good luck!

Apparently, most insects do not like peppermint oil, so you could make up a spray with water and the oil and use it where you have the biggest problem.