[Sony Xperia XZ2 ROMs, Kernels, Recoveries, & Other] MartinX3:
https://www.xda-developers.com/how-...ess-updates-affect-custom-development-on-xda/

Usually slotted are BOOT, DTBO, SYSTEM, VENDOR, VBMETA

The XZ2 as example has 78 partitions., but many of them are single slot.

(bootloader) partition-type:xbl_config_b:raw
(bootloader) partition-type:xbl_b:raw
(bootloader) partition-type:xbl_config_a:raw
(bootloader) partition-type:xbl_a:raw
(bootloader) partition-type:rddata:raw
(bootloader) partition-type:userdata:ext4
(bootloader) partition-type:fsc:raw
(bootloader) partition-type:fsmetadata:raw
(bootloader) partition-type:Qnovo:raw
(bootloader) partition-type:diag:raw
(bootloader) partition-type:appslog:raw
(bootloader) partition-type:frp:raw
(bootloader) partition-type:keystore:raw
(bootloader) partition-type:misc:raw
(bootloader) partition-type:cdt:raw
(bootloader) partition-type:fsg:raw
(bootloader) partition-type:modemst2:raw
(bootloader) partition-type:modemst1:raw
(bootloader) partition-type:logdump:raw
(bootloader) partition-type:logfs:raw
(bootloader) partition-type:toolsfv:raw
(bootloader) partition-type:limits:raw
(bootloader) partition-type:spunvm:raw
(bootloader) partition-type:msadp:raw
(bootloader) partition-type:apdp:raw
(bootloader) partition-type:sec:raw
(bootloader) partition-type:system_b:ext4
(bootloader) partition-type:vendor_b:raw
(bootloader) partition-type:oem_b:raw
(bootloader) partition-type:dtbo_b:raw
(bootloader) partition-type:vbmeta_b:raw
(bootloader) partition-type:rdimage_b:raw
(bootloader) partition-type:boot_b:raw
(bootloader) partition-type:dsp_b:raw
(bootloader) partition-type:bluetooth_b:raw
(bootloader) partition-type:modem_b:raw
(bootloader) partition-type:system_a:ext4
(bootloader) partition-type:vendor_a:raw
(bootloader) partition-type:oem_a:raw
(bootloader) partition-type:dtbo_a:raw
(bootloader) partition-type:vbmeta_a:raw
(bootloader) partition-type:rdimage_a:raw
(bootloader) partition-type:boot_a:raw
(bootloader) partition-type:dsp_a:raw
(bootloader) partition-type:bluetooth_a:raw
(bootloader) partition-type:modem_a:raw
(bootloader) partition-type:tzxfl_b:raw
(bootloader) partition-type:tzxflattest_b:raw
(bootloader) partition-type:xfl_b:raw
(bootloader) partition-type:qupfw_b:raw
(bootloader) partition-type:devcfg_b:raw
(bootloader) partition-type:cmnlib64_b:raw
(bootloader) partition-type:cmnlib_b:raw
(bootloader) partition-type:keymaster_b:raw
(bootloader) partition-type:abl_b:raw
(bootloader) partition-type:hyp_b:raw
(bootloader) partition-type:tz_b:raw
(bootloader) partition-type:aop_b:raw
(bootloader) partition-type:tzxfl_a:raw
(bootloader) partition-type:tzxflattest_a:raw
(bootloader) partition-type:xfl_a:raw
(bootloader) partition-type:qupfw_a:raw
(bootloader) partition-type:devcfg_a:raw
(bootloader) partition-type:cmnlib64_a:raw
(bootloader) partition-type:cmnlib_a:raw
(bootloader) partition-type:keymaster_a:raw
(bootloader) partition-type:abl_a:raw
(bootloader) partition-type:hyp_a:raw
(bootloader) partition-type:tz_a:raw
(bootloader) partition-type:aop_a:raw
(bootloader) partition-type:ddr:raw
(bootloader) partition-type:devinfo:raw
(bootloader) partition-type:ssd:raw
(bootloader) partition-type:persist:raw
(bootloader) partition-type:xflkeystorebak:raw
(bootloader) partition-type:xflkeystore:raw
(bootloader) partition-type:LTALabel:raw
(bootloader) partition-type:TA:raw

You're welcome in advance!