Icy Rock: Extends the duration of Hail weather set by the holder from 5 turns to 10. In addition, the holder's Hail cannot be overridden by any other weather while the holder is on the field. The holder is immune to Hail damage.
Flavour: Um… it's a rock that summons hail I guess? Basically just an extension of its old effect.
Competitive: Now anyone that learns Hail can be a usable Hail setter!
Snowball:
Hold effect: The holder takes 20% less damage from Ice-type moves and is immune to Hail damage. Every time the holder is hit with an Ice-type move and every turn the holder is exposed to Hail, the base power of their own Ice-type moves increases by 10%. This effect stacks with itself (additive, not exponential; ex. 100%, 110%, 120%, 130%, etc. and not 100%, 110%, 121%, 133.1%, etc.) and lasts until the holder switches out. The power boost caps at a x3 multiplier. (If you manage to get it that high, most likely your opponent is stalling and you're playing a Hail team.)
Fling effect: When Flung, the Snowball has 30 base power, plus 20 more base power for every time the holder has been hit with an Ice-type move and every turn the holder has been exposed to Hail since its last switch-in, plus 20 more base power for every time the holder has Flung a Snowball since its last switch-in. A Flung Snowball also has a 20% chance to Freeze the target. The Snowball has the unique trait of having a 50% chance to Recycle itself every turn after being Flung; this becomes a 100% chance in Hail. (The auto-Recycle occurs before any applicable weather damage, so if Hail is up the Snowball will be back in time to prevent Hail damage and gain another Ice boost.)
Flavour: The Snowball builds up as ice and snow collect into it, and the collected snow is then used to power their own Ice-type attacks. Snowballs are also used for snowball fights (in fact, that's how they're normally used), so why not Fling it? It Recycles itself because the holder can just pack together some snow to make a new one. And with its Fling damage increasing every time it's used, the power can snowball out of control!
Competitive: Helps some Pokémon with their Ice weakness while also powering their own Ice coverage. It also helps out with Hail's viability by slowly powering up Ice moves while Hail is in effect!
Never-Melt Ice:
Hold effect: The holder takes 40% less damage from Ice- and Fire-type moves.
Fling effect: When Flung, the Never-Melt Ice has 50 base power. If the target is Frozen or Burned, that status is cured and Fling's base power is multiplied by 3.
Flavour: Never-Melt Ice is supposed to never melt, hence the name, so it confers resistance to both Fire and Ice.
Competitive: It's almost like the ability Thick Fat on an item slot. I'm sure several Pokémon would appreciate this quite a lot. Scizor, for example, might almost be able to live a Fire-type move, taking only 2.4x damage instead of 4x. Many Grass-types like having two of their common weaknesses reduced to only a 1.2x damage multiplier, too.
*note: You could buff it to actually be Thick Fat on an item slot, but I feel like that might be too good.
Casteliacone:
Acts as a Lum Berry. In addition, the Pokémon that eats it has the base power of its Ice-type moves multiplied by 1.5 until it switches out. When Flung at another Pokémon, it hits for 10 base power and the target gains its effects. Can be eaten with Bug Bite or Pluck, or destroyed with Incinerate.
Flavour: It's ice cream, so it boosts the power of Ice-type moves.
Competitive: You will learn that Will-O-Wisping a Weavile or Mamoswine is a bad plan.
Icicle Plate:
Holder's punching and kicking moves become Ice-type and have their base power multiplied by 1.5.
Flavour: Since the Fist Plate no longer boosts Fighting moves directly, other effects are needed for the different Plates. Similarly to the Fist Plate, the Icicle Plate can be used as if it were brass knuckles (despite the fact that this is obviously heresy). The elemental energy from the world's creation that clings to this piece of holy scripture causes it to deal Ice damage when used as a blunt weapon.
Competitive: Put Ice coverage on everything! (Also Mega Kick is suddenly viable as it's now a 180 base power Ice move lol.) Basically the same as the Fist Plate.
Possible change for the Fist Plate to go with: changes punching and kicking moves to be Fighting-type along with boosting them.
Flavour: Um… it's a rock that summons hail I guess? Basically just an extension of its old effect.
Competitive: Now anyone that learns Hail can be a usable Hail setter!
Snowball:
Hold effect: The holder takes 20% less damage from Ice-type moves and is immune to Hail damage. Every time the holder is hit with an Ice-type move and every turn the holder is exposed to Hail, the base power of their own Ice-type moves increases by 10%. This effect stacks with itself (additive, not exponential; ex. 100%, 110%, 120%, 130%, etc. and not 100%, 110%, 121%, 133.1%, etc.) and lasts until the holder switches out. The power boost caps at a x3 multiplier. (If you manage to get it that high, most likely your opponent is stalling and you're playing a Hail team.)
Fling effect: When Flung, the Snowball has 30 base power, plus 20 more base power for every time the holder has been hit with an Ice-type move and every turn the holder has been exposed to Hail since its last switch-in, plus 20 more base power for every time the holder has Flung a Snowball since its last switch-in. A Flung Snowball also has a 20% chance to Freeze the target. The Snowball has the unique trait of having a 50% chance to Recycle itself every turn after being Flung; this becomes a 100% chance in Hail. (The auto-Recycle occurs before any applicable weather damage, so if Hail is up the Snowball will be back in time to prevent Hail damage and gain another Ice boost.)
Flavour: The Snowball builds up as ice and snow collect into it, and the collected snow is then used to power their own Ice-type attacks. Snowballs are also used for snowball fights (in fact, that's how they're normally used), so why not Fling it? It Recycles itself because the holder can just pack together some snow to make a new one. And with its Fling damage increasing every time it's used, the power can snowball out of control!
Competitive: Helps some Pokémon with their Ice weakness while also powering their own Ice coverage. It also helps out with Hail's viability by slowly powering up Ice moves while Hail is in effect!
Never-Melt Ice:
Hold effect: The holder takes 40% less damage from Ice- and Fire-type moves.
Fling effect: When Flung, the Never-Melt Ice has 50 base power. If the target is Frozen or Burned, that status is cured and Fling's base power is multiplied by 3.
Flavour: Never-Melt Ice is supposed to never melt, hence the name, so it confers resistance to both Fire and Ice.
Competitive: It's almost like the ability Thick Fat on an item slot. I'm sure several Pokémon would appreciate this quite a lot. Scizor, for example, might almost be able to live a Fire-type move, taking only 2.4x damage instead of 4x. Many Grass-types like having two of their common weaknesses reduced to only a 1.2x damage multiplier, too.
*note: You could buff it to actually be Thick Fat on an item slot, but I feel like that might be too good.
Casteliacone:
Acts as a Lum Berry. In addition, the Pokémon that eats it has the base power of its Ice-type moves multiplied by 1.5 until it switches out. When Flung at another Pokémon, it hits for 10 base power and the target gains its effects. Can be eaten with Bug Bite or Pluck, or destroyed with Incinerate.
Flavour: It's ice cream, so it boosts the power of Ice-type moves.
Competitive: You will learn that Will-O-Wisping a Weavile or Mamoswine is a bad plan.
Icicle Plate:
Holder's punching and kicking moves become Ice-type and have their base power multiplied by 1.5.
Flavour: Since the Fist Plate no longer boosts Fighting moves directly, other effects are needed for the different Plates. Similarly to the Fist Plate, the Icicle Plate can be used as if it were brass knuckles (despite the fact that this is obviously heresy). The elemental energy from the world's creation that clings to this piece of holy scripture causes it to deal Ice damage when used as a blunt weapon.
Competitive: Put Ice coverage on everything! (Also Mega Kick is suddenly viable as it's now a 180 base power Ice move lol.) Basically the same as the Fist Plate.
Possible change for the Fist Plate to go with: changes punching and kicking moves to be Fighting-type along with boosting them.