Reddit reviews BCW Topload Holder (25-Pack), 6x8

Soft: https://www.amazon.com/gp/product/B07JHZBVQ9/ref=ppx_yo_dt_b_asin_title_o02_s01?ie=UTF8&psc=1

Hard: https://www.amazon.com/gp/aw/d/B000VVCPUG?psc=1&ref=ppx_pop_mob_b_pd_title

I recommend Ultra Pro for soft and hard. BCW does not have a soft sleeve and Ultra Pro's soft sleeve does not fit inside a BCW. With Ultra Pro you can easily double sleeve.

Titan Size Soft (not perfect but best fit. Does not perfectly fit inside the hard one, it will hang out of the top by a few millimeters but the card is fully covered): https://www.amazon.com/gp/product/B00TJQZ31W/ref=ppx_yo_dt_b_asin_title_o02_s02?ie=UTF8&psc=1

Titan Size Hard (not perfect but best fit. Putting a soft inside does hang out of the top a little bit but the card is fully covered): https://www.amazon.com/gp/product/B00V0EYDYY/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

As for combiners, unfolded they are the same size as a regular character so they will fit with these the same way. I leave them fully unfolded inside a sleeve and then use a marker of some kind to show their mode. My tip for that is that a character card is exactly the size of two battle cards. So any spare battle card can be used to cover up one side or the other.

I found these to work perfectly for Metroplex

BCW Topload Holder (25-Pack), 6x8

https://www.amazon.com/dp/B00V0EYDYY/ref=cm_sw_r_cp_apa_i_r7jwCb88DD0GN

http://imgur.com/gallery/YgX5RYi